Having your fun - part 1
Launching basics
Now you've got your frozen Elites ready and waiting, it's time to launch them. In the introduction I already mentioned rocketing and needling then backing off across a release line, but here's a lot more detail.
Killing your Elite
A frozen Elite needs killing before you can launch him. He's initially still alive even though he may no longer have grasp of his weapon, frozen close to his hand. You may notice a weird anti-aim effect that seems to repel your aim (unless holding an unzoomed sniper rifle). Even if initially absent however, it could manifest after a blast which doesn't quite kill him. It varies in strength and can be very uncomfortable. I'm glad the Elites don't normally employ this defence technology!
Fortunately any anti-aim effect ceases once he's dead, which might be after a first rocket blast on the ground, though you can actually kill him any way you like. If the anti-aim effect is strong it can be awkward to blast the ground near him, so you might prefer to just let some needles home in, which they do very strongly while he remains alive. Usually the first needle bang would kill him. Even melee can be used to kill him (best done from the rear, unless you've pre-weakened him to the point where a whack from any direction will do), but in that case he won't scream on launch. For the chance of a scream you need to kill him explosively.
His death causes a randomized number of plasma grenades to be released. It seems to be either zero or a certain fixed number for that particular Elite. Typically his weapon is released too, i.e. becoming unfrozen. With some Elites however, the weapon remains in place if you kill him with melee or non-explosive weapon fire (often the case with Elites relatively high off the ground, or pre-frozen Elites on the ground). When the Elite is dead you'll be able to pass through him if you couldn't before. Sometimes an Elite is like that even when still alive however.
Rocketing and other blasting
Rockets will be the usual thing you blast an Elite with to make him fly off, but you could also use Scorpion shells (powerful but clumsy for aiming), Banshee bolts (let it rest stationary on the ground for easiest use once he's dead) or even grenades. You can aim your firework according to where you place your blasts. Typically you'll want to send him high, but if he's close to the ground you can easily launch him at a relatively shallow angle, perhaps to get him ricocheting around. You could also get low trajectories by blasting a vertical surface he's close to, such as the cliff wall. You can do your blasting before or after your needling, or mix it all up; I don't think it makes any difference to the eventual effect.
More blasts mean more speed, as their effect is cumulative. Interestingly, the cumulative blast affects blood clouds. You'll see them flying off faster and faster, perhaps eventually to start decorating a distant cliff wall - or even the ceiling if you blast long enough! Incidentally, you might think that an Elite high above a ground blast would get significantly less boost than one low down, but actually blast effect doesn't seem to tail off with distance like that.
Needling
Once your Elite is dead, needles don't home in on him (and the reticle won't turn red) so you need to stand fairly close if you want to avoid any missing. Not too close though, or you could get damaged by a needle bang and have to wait for your shield to recharge. It could also jolt your aim or deflect incoming needles, causing needles to miss. If you're not tagging him with plasma grenades yet, you'll find that there's a bang every 23 needles, starting from needle 29. Nearby plasma grenades could be set off, so you might want to pick them up to avoid a nasty accident.
The chest makes a nice big target when needling, but if you inject multiple areas around him it can make for a more striking effect when he's airborne, with a more expansive pink trace. It's important to realize that needles in different places can give different effects on his trajectory however. In flight he tends to be face-down, so if a needle bang goes off on his chest it'll give him an upwards push, helping him stay airborne longer. The boosting effect of needle bangs is considerable in fact. Explore the possibilities.
In terms of post-release effect, you get about 2 bangs per clip, at a rate of one bang per second or thereabouts. On PAL Xbox (which runs at 25 fps), the gap between needle bangs is normally 23 frames, but you may sometimes get a gap of only 22 when there are plasmas going off along the way. I suspect that such timing anomalies are due to the game having trouble processing things fast enough.
As you inject needles, there's a certain amount of wastage because earlier ones gradually go off. But the expiry rate is less than the addition rate, so overall you'll still be increasing the number of needles in him. When he's unfrozen, the needle bangs will follow the order of injection. So for example, if you pumped a few clips into his chest then a few into a foot, you'll get a sequence of bangs at the chest first, then at the foot.
Each needle bang on the frozen Elite will contribute its blast effect to the eventual launch. Bangs from needles in the chest contribute upwards lift, and with enough bangs you can potentially launch him high with needles alone! Bangs on his feet contribute upwards lift too. Bangs on his back are quite different and tend to push him downwards.
When using a lot of needles, you may eventually seem to be firing invisible ones, and there's no muzzle flash. In my experience this tends to start happening around clip 23. You've reached the limit of how much the game can render. The needles are actually still there; they're just not being rendered. They still give a sound effect on hitting the body, and they'll still contribute to the bangs later. So by all means continue needling as long as you stay within the clip tolerance. You can likewise find yourself short of visuals if subsequently firing rockets, but they're still there and having an effect. The game can remove loose plasma grenades as needles build up, but I've only ever noticed that after using 40+ clips, so it's not likely to be much of a concern.
Avoiding ammo wastage
If you've just emptied a needler and you move over a full one, you'll lose the needles in the latter's current clip, and you'll also have to draw on another needler if you want to top up. To avoid losing needles and potentially end up with a full needler faster, first swap your empty with some other weapon, then swap that for a new needler. For me the 'other weapon' would usually be the sniper rifle, deliberately left in front of my needler stash; and after the swapping is over, it ends up near where it came from, ready for next time. The same efficiency remark goes for rocket launchers.
Plasmas for good measure
You may like to finish off by tagging the Elite with a few plasma grenades so they give him a boost in mid-air, possibly shooting him up higher or maybe putting a big kink in his trajectory. While he remains frozen however, the grenades will normally just fizz away on him. They also give off nice streamers under the influence of the cumulative blast, so you'll have a good idea of which direction he's going to fly off in. For the most extreme boosting effects I suggest concentrating the grenades in one area of his body. The chest is an obvious target, but as with needles, the location of a plasma grenade on the body can produce different effects, so keep that in mind and try things out.
Releasing
To launch an Elite after doing your worst, you need to cross the release line mentioned and shown in my basic set-up routine, causing him to unfreeze and start experiencing the combined effects of what you've done to him. Typically that means backing off in the rough direction of the tower. Don't ask me why crossing a line triggers this release though; it's a mystery to me and we'd probably need a Bungie programmer to tell us. The release line is actually two-way, by which I mean that if you were to instead kill your frozen Elite from the other side of the line, he'd still launch when you cross it.
The moment he's released from his freeze, everything you did to him starts to take effect. You'll get a death cry - potentially a nice satisfying scream if you killed him explosively - and the cumulative blast sends him flying. The needles start going off in a succession of explosions, and in due course you'll also get bangs from any plasma grenades you decorated him with. If you're doing a big launch you'll probably want to've switched to a sniper rifle to help you follow him when distant. You'll also be able to get a good view of the clouds of blood flying off him from the needle bangs.
I didn't realize there was a specific line involved until investigating for my 2010 revision. Originally I just thought you needed to back off in a certain direction to cause a release, and it was all a bit mysterious.
Tag launching
When revising this article in October 2010 in preparation for doing some movies, I discovered a new and highly satisfying launch method which I call tag launching. Basically, you tag your Elite with plasma grenades on his feet or at least somewhere low down, and inject him with just the right amount of needles so that when he's released, the grenades go off almost instantly, boosting him up with a massive bang. I never realized that was possible before; I think I'd always been doing my tagging last, otherwise I might've cottoned onto it sooner. Rockets or other blasting can be used to augment the boost if desired (possibly to effect aiming), and you also have the option of preceding the grenades with extra needles to keep the pink trace going longer.
Try this 4-grenade tag launch as an example. Tag each of his feet with 2 plasma grenades (you may need to be pretty close if he's exhibiting the anti-aim effect, unless you're holding an unzoomed sniper rifle), then inject him with 59 needles and release him. BLAM! Up he goes, potentially higher than the second ledge running around the area. If you want a few more needle bangs to help last through the flight, give him two clips first then the 4 plasmas and 59 needles. That's my 99-needle special, from which you should get 10 needle bangs.
After some investigation I realized what was going on here, so let me explain as best I can before getting to some more examples. This is all for PAL Xbox. On NTSC/PC the details may be slightly different.
Running down a fuse
When you tag a frozen Elite with a plasma grenade, each successive needle or plasma grenade (tag-object as I'll collectively call them) takes it a step closer to exploding, as if its normal fuse of around 2.4 seconds is getting shorter and shorter. In 62 or 63 steps it would actually explode on the frozen Elite and add some boost to the eventual launch, but what we're more interested in is what happens if the Elite is released before things go that far. In that case the explosion delay depends on that fuse I mentioned; and you thus have a way of controlling the delay. In particular, if the grenade was taken to the very brink of exploding, namely by the application of 61 or 62 tag-objects, it'll go off almost instantly.
In practice you'd probably be tagging the Elite with multiple grenades. If you apply them as a group then apply the right amount of needles to take the first grenade to the brink, they'll end up going off in what looks like one big bang, but they're actually going off one after another, having had their individual fuses run down to varying extents. If you use enough grenades you'll potentially see an extended plasma plume formed from the explosions, such as in the accompanying picture of an 8-grenade tag launch, comprising 8 plasmas followed by 55 needles.
If the Elite shoots off at extreme speed due to extra boost provided by Scorpion blasts perhaps, the grenade explosions can actually be seen separately rather than blending into a plume, and the first bang can be high up, showing that it wasn't actually instant. The picture on the right illustrates all this using that earlier 4-grenade tag launch assisted by 20 Scorpion blasts. As you can see, the final grenade has just gone off.
Going back to that example of applying 4 plasma grenades then 59 needles, notice that the first grenade gets followed by 62 tag-objects. That takes it to the very brink of exploding, with the other grenades not far behind. If you want to check, stand well back and add one more needle, and you'll see that the first grenade will explode. Add another and the second grenade explodes; and so on.
For any given sequence of needles and grenades, ending with a grenade, you can check how many subsequent needles are required to take the first grenade to the brink, simply by applying them until you get a grenade bang, then subtracting 1. You'll then know what to do in future. If you don't want to bother with such checking however, you could just play safe and apply only 61 tag-objects after the first grenade. That will either take it to the brink or one step away from the brink - which is still going to result in a near-instant bang when the Elite is released.
More on the tagging
Earlier I mentioned tagging the Elite on his feet or at least somewhere low down, so the explosions boost him upwards. But because the grenades are going off progressively rather than all at once, that only really applies to the earliest grenades. By the time later grenades are going off, he could already be in his usual face-down attitude, in which case those grenades might as well be on his chest, as far as providing boost goes. In fact, being on his chest might even be better for upwards boost, when he's in that attitude.
If the Elite is sufficiently far off the ground you can actually tag him on the soles of his feet (you might need to crouch). I tested using this for tag launching but disappointingly it didn't seem to provide any more boost than just tagging him on the top of his feet. It looks amusing though.
Basic tag launches
I already mentioned a 4-grenade tag launch, in which you tag with 4 grenades then apply 59 needles. With 2 grenades you should instead use 61 needles, while for 6 you'd use 57. In general, for N grenades use 63 - N needles, as long as N is no more than 11. Getting more extreme, for N from 12 to 25 use 62 - N needles. Above that, you'd better check for yourself! Incidentally, 1 grenade isn't really enough, but 2 give significant boost, and with the additional lifting effect of needle bangs going off on his chest he can rise above the level of the first ledge. With 4 he can reach as high as the second ledge. For comparison, if you were using rockets and 59 needles, you'd need 5 rockets to get close to that height.
With those launches your needles won't last long into the flight. For more needle bangs you'll need to apply some needles before your first plasma. When you do that however, the number of needles to add after the last grenade won't necessarily be the same as before. It could differ by a needle. For example, if you apply a clip then 4 grenades, you should only then apply 58 needles, not 59, else you'll set the first grenade off.
Timing in general
I've already mentioned the idea of applying plasma grenades for a delayed bang in mid-air, and of using them to provide an immediate boost in tag launching. In this section I'll talk about exploiting timing in general, not just in regard to plasma grenade bangs but also the first needle bang. The details here are for PAL Xbox. On NTSC/PC I suspect things will be slightly different.
Timing the first needle bang
Analogous to controlling the delay until the first grenade bang, you can control the delay until the first in-flight needle bang, and in particular you can make it go off the moment your firework launches. I'll explain.
When talking about needling, I mentioned that if you're not applying plasma grenades yet, you get a bang every 23 needles, starting from needle 29. Plasma grenades add a slight complication because they can be counted in place of needles in making up those totals of 29 or 23. For example, if you apply 28 needles then a plasma grenade, you'll get a needle bang, just as if you'd added another needle.
Ignoring that complication, let's suppose you've just had a needle bang on your frozen Elite. If you were now to unfreeze him, the first in-flight needle bang would go off after about a second. If instead you add a dozen needles first (approximately half of 23), it would go off in about half a second. Getting the picture? The closer you come to setting off another needle bang on the frozen Elite, the sooner you'll get that bang when he's unfrozen.
The most interesting way of exploiting this control is to take the impending needle bang to the brink by stopping just short of the next dose of 23, or the first dose of 29, so that when you unfreeze your Elite he'll launch with a satisfying needle bang, rather than launching without any explosion effect. It's analogous to how you take things to the brink for a tag launch, and it looks and sounds good. There's an example in the first launch of BCM23, where I used 140 needles then 3 plasmas. Now, 29 + 5 x 23 = 144, which means that if I'd added just one more needle or grenade, I would've completed the fifth dose of 23 and got my next needle bang on him. I stopped just short of that, hence got the bang on launch. I also arranged to have near-instant needle bangs for the double launch, by giving each Elite 49 needles then 2 plasmas, stopping just short of the total of 52 (29 + 23) which would give the next needle bang. Incidentally, 29 + 4 x 23 = 121, which means that if you merely inject the Elite with 6 clips, he'll launch with a needle bang.
Spaced out grenade and needle bangs
You can use your control over grenade explosion delays to get a discrete sequence of bangs. The effect on the released Elite can be quite amusing when he gets jolted around in rapid succession by grenade bangs and needle bangs. For example, apply a grenade then a clip of needles, a grenade then a clip, a grenade then 19 needles, then a grenade. Add rockets if you want (I think you'll need them if you don't have pre-frozen Elites on the ground, as it doesn't seem to work too well otherwise). But that's only a simple example. What you should really explore is using more grenades and having fewer needles between them, so you get a higher rate of grenade bangs. Lots of potential there!
UPDATE: For some recipes in which plasma bangs work together with needle bangs to give rhythmic effects, see BCM278 (involving a frozen gold Elite on The Silent Cartographer), and read the movie commentary for details.
Two-stage or three-stage boost
How about arranging a two-stage grenade boost? For example, apply 2 grenades then a clip of needles then another 2 grenades then 39 needles. You'll get a grenade bang on launch - from the first two grenades - then another grenade bang a bit later from other two grenades. Or for a three-stage boost, you could apply 2 grenades, a clip, 2 grenades, a clip, 2 grenades, and 17 needles. You can see both of those examples in BCM24. You don't have to follow those exact recipes though; there's plenty you can vary and still get a two-bang or three-bang effect.
Double launching
You can potentially launch the Elites together, which typically makes for extra spectacle and noise. It's especially good to hear two screams at once! For the best effect I'd suggest doing the same things to each Elite, to try and get the most synchronized look. The sounds won't necessarily match for both Elites however. Even though you see two needle bangs going off simultaneously, the game might only give the sound for one of them. Some sort of technical issue I guess.
Instead of trying to get them doing the same thing though, another idea is to try and engineer the bang timing so things are complementary, i.e. with bangs alternating between the Elites. I've yet to explore this idea properly but I think the potential is good.
Parallel paths
Even if you have the Elites close together - hence hard to rocket individually - it can still be possible to get them both shooting up vertically if you do your rocketing right. To help you see what's going on, have some plasma streamers going, as mentioned in the Precision aiming section. If you blast the ground between the Elites, obviously that's making the Elites head away from each other. But you can balance things out (getting the streamers closer to vertical) by blasting to each side, affecting the Elites to different degrees. You might not need any blasts in the middle at all. Play around with things and you should get the idea.
If you can get them shooting off on parallel paths close together and then some plasma grenades go off, that's liable to suddenly boost them apart from one another, which should look pretty amusing.
Crossing paths
As well as the possibility of sending Elites up on parallel paths close together, there's also the idea of having more separated Elites and making their paths cross. For one thing, it looks nice. But for another, with good timing and aiming you might be able to get plasma grenades to go off on them just as they're close together, boosting them apart as just mentioned. There's quite a nice crossover early in BCM24.
Needle rendering issue
When you start needling your second Elite, you may notice that the needles aren't looking as bright and glowing. Actually this isn't to do with using two Elites at all. In general it seems that after about 60 needles are being rendered (whether embedded in one Elite or two), subsequent needles lack the usual diffuse pink glow added around the actual needle. I assume the game is limiting itself to try and keep a lid on how much work it has to do, out of concern for keeping the framerate up. If for some reason you want your Elites to look similar in regard to needle brightness, share out the first 60 needles fairly equally.
Clip tolerance issues
When preparing a double launch, the total number of needle clips you use had better stay within the clip tolerance, else one of the Elites may vanish. In fact you may find that when you share out your needles between the Elites, the number of clips you can reliably use is slightly lower than the tolerance. At any rate, that's what I sometimes experienced with my old way of setting things up, in which I was getting much lower clip tolerances in general.