A special Grunt who… likes a bit of posthumous swimming? Surely not.

Posted September 24th 2026

• The Grunt
• Swimming phenomenon
• Swim attacking
• Setting up for convenient play
• Floating death anomaly
• Further observations
• What's going on?
• Twitching trick

In the sleeping Grunts room after you part ways with any Marines, there's often a Grunt in a small recess at the end of a long block feature in the central area. The 'cubby-hole Grunt' I call him, on account of his location. A rather interesting and unusual fellow as it turns out!

He's there about half the time (it may actually be about 45% of the time, based on some quite extensive tallying I did), spawning randomly along with the other covies when you go through the relevant loading point. There's a passage checkpoint just before that loading point, so if you find that you don't have a cubby-hole Grunt, you can just keep reverting until you do, something you can quickly check.

The Grunt can be red or orange, and a fin-back or curl-back. And as with all the other Grunts in this room, he'll initially be having a nice snooze. His position and orientation always seem the same.

Unusual confinement

Something very easily noticed is that the Grunt seems thoroughly confined to his cubby-hole. Not only does he stay within it while alive, but his body stays inside it after he's dead. Alive or dead, he apparently can't be blasted out! Try as many rockets, grenades and needle bangs as you like; they won't work. There actually seems to be an invisible barrier over the end, which I expect provides the reason. It blocks bodies. Not only can his body not come out, but also, it seems that bodies can't be blasted in.

But now we come to the cubby-hole Grunt's big claim to fame. Players who've been through the room a good number of times will likely have seen him do something rather amusing on occasion. Namely, when killed he may go into what looks like a swimming animation, anchored in mid-air! 'Air swimming', I've sometimes called it. You can see the phenomenon showcased in BCM688.

But it's not swimming of course; it's actually the standard death flight animation (with amusing flailing arms), except held in place. Weird! And by the way, you'll typically only see this happen in a relatively central stretch of the cubby-hole.

Players have undoubtedly remarked on this since the early days of the game, and no doubt there were some video snippets posted here and there (I haven't yet tried to search for them, or for possible discussion).

Time limitation

It may look like the swimming will continue indefinitely if left alone, but actually it appears to be limited, typically ending after around 4 minutes, based on some testing I did. The Grunt just flies off from his anchor point and settles on the ground. An example is shown in BCM690. Swimming can last significantly longer if you're doing attack work though (see later). I've had it last over 6 minutes. I think this may be to do with the framerate slowdown you can get with such work.

Ways of getting him swimming

Although swimming can be obtained randomly during combat using most or maybe all ways of killing him, that's not the easiest way to get it. For proper control you want him to be asleep. That's what I'll assume now.

While a pistol headshot can give a good success rate when delivered appropriately (be square-on to him or around to the left from that), it seems to me that a more reliable choice is to use the particular melee method shown in BCM690 at 3:35, something I arrived at through laborious experimentation and testing. In that method you wedge in to the side and strike somewhat across him (see pic). Tested on three set-ups, it always gave me a success rate of over 80%. In fact, 84% or better.

There's also an excellent method with a sniper rifle, if you happen to have one with you. Demonstrated in BCM693 at 1:28, that gave me a success rate of over 90% for each of three set-ups I tested it on. In fact, 92% or better. That makes it the best-performing method I know of.

With all these methods, the Grunt gets knocked back and then bounces forward off the back of the cubby-hole, into the death flight animation. There are a few slo-mos of that in BCM690.

Once you've got the Grunt swimming, you can play about by explosively attacking him with needling, grenades and rockets, seeing what happens. Sometimes a blast may end the swimming, so he finally settles. But the swimming also has a degree of robustness, so it's quite possible that it continues, although perhaps he's been rotated. Talking of which, you sometimes get some gradual slow rotation after a blast.

You can see some examples in BCM688, featuring plasma grenades and needling. Tagging him can be fun, not least because the stuck grenade emits a downwards streamer. Also, if you can manage to tag him on a paw, the grenade will whirl around.

Blasts can not only rotate him, but also skew him into a wonky attitude and alter his position, transforming the look of things considerably (see pic). In fact, with extensive blasting he can end up partially absorbed into the scenery! You can see such extreme situations in BCM691.

Incidentally, I had lots of needlers available in the set-up used there, but bear in mind that by using drop reloading you can use a single needler to needle indefinitely. It's less convenient though.

Blast containment

In connection with this business, let me mention that blasts are often 'contained' within the cubby-hole, meaning that you're unaffected even if close. Other times though, you may take damage as normal. It seems a bit random. Or at any rate, if it's not random, I don't currently have an understanding of the workings. There are also times when a rocket is mysteriously blocked from entry into the cubby-hole (which if the Grunt is alive, can give the appearance of him having survived a direct hit).

Before going any further in regard to the weirdness involved with this Grunt, let me describe how you can easily create a set up for convenient play. You can see a demo of this at the start of BCM690.

Once you find that you've got a cubby-hole Grunt, stealthily kill the Elites, along with any Grunts who might pester you too much when you're having fun later. You could kill all the other Grunts if you want, but you may like to leave some alive for grunty chatter and whatnot. They can provide casual background amusement.

Optionally, arrange some spare weapons to maybe use on the Grunt later. The covies killed here can provide you with a plasma rifle and plasma pistol, but any other weapon type will need to be brought along from earlier. For basic fun I'd recommend having arrived with a pistol and needler. But there's also fun to be had with a rocket launcher and sniper rifle; and you might want a few extra needlers, by the way.

At the start of the narrow passage to the lift, there's a checkpoint trigger. Keep that checkpoint delayed with jumping, and get it near your Grunt (you'll have to be a fair way back from him, so the game doesn't consider him a threat). I'd also suggest having a fully charged flashlight on, to illuminate things better (I definitely wanted that for my movies at least). Finished!

Option for killing the music

With what I've described so far, you'll have the room's mellow music going. If you prefer not to have the music though, just adjust the work slightly by including sending the lift up (get around behind the panel to operate it, so you don't ride up). The music will soon fade out.

Modifying later

If you later want to create a modification of your set-up (e.g. you could be in a particular spot, ready to try something with a particular weapon), bear in mind that a new delayed checkpoint can be conveniently obtained as follows. Ride up in the lift. At the top (as soon as you like), hit the switch to ride down again, and also start jumping to delay the checkpoint that got triggered as you reached the top. Now just keep it delayed until ready to get it. Another option for checkpointing is to use a delayed tunnel checkpoint.

It turns out that the swimming isn't the only weird thing this Grunt can do. In the course of working with him for my first movie instalment, I witnessed something that was completely new to me, and which I soon showcased in my second instalment BCM689. The 'floating death anomaly' as I called it.

What happens is, the Grunt floats off the ground for a few seconds, protesting with "Not again!" or suchlike, then dies and goes into the death flight animation, i.e. the 'swimming'. In fact, in all regards (including being a red dot on your tracker while still alive) he acts as if he's falling and then dying, just like a Grunt who went off a bridge or something, except that it's all anchored within the cubby-hole.

A further aspect is that while he's floating, you experience a strong anti-aim effect (if using your aim thumbstick), which makes it hard to move your aim onto him. It's repelled away. It's just like the anti-aim effect you can get with frozen covies.

Ways of getting the anomaly

Getting the anomaly seems considerably harder than just getting the swimming, which is presumably why I'd never seen it before, despite having slain the covies in that room countless times in the past. However, nor is it super difficult to get.

Ideally starting with a sleeping Grunt, try using a few non-killing shots to force him backwards from his central spot. It's likely to take multiple tries, but you'll probably get lucky before long. You can see some examples in the aforementioned movie.

There are also a few different ways shown in BCM693, including one where he's shocked awake from distance with a sniper rifle. With that method you can watch him with a zoomed view (see pic).

While working with that method, I realised also that by releasing the aim thumbstick before the he starts floating, I could get a good steady view, avoiding the anti-aim effect. That's a nice way to do things. Ideally you should quickly adjust your aim before releasing the thumbstick, so he'll be fairly central in your view. It needs a bit of finesse, but it's something you can get used to.

In this section I'll note a few other observations. But let me first mention that in all my work on investigating this Grunt, I've used Heroic. There may or may not be differences when using other difficulty levels.

Swimming after settling

Although it tends to take a bit of work, swimming can also be obtained by blasting his settled body. In this case the swimming is sometimes in an unusual location, such as high up and to the left (see pic). You'll see examples of that in BCM692, my movie on the topic. You'll also see some instances of swimming spontaneously ending within moments, another oddity.

Body-lifting weirdness

In my written commentary for BCM692, namely concerning a clip at 2:56, I remarked on something weird I noticed. A tag-bang on the settled Grunt caused him to start swimming, but his body didn't jerk up into position. Instead there was a short delay and then it rose up smoothly, as if pulled or pushed. Very strange (and I've seen it other times too). This really needs some explanation.

Strange settling

Sometimes the Grunt's body settles strangely, as if resting on an invisible surface (possibly angled). You see various configurations, as if there are multiple possible invisible surfaces (which may or may not be there at any given time). It's another mystery, and I wonder if it has some bearing on the other weirdness going on with the Grunt (the swimming and floating death anomaly). For examples see the start of BCM693.

Cramped running

The Grunt is so closely confined, he usually just does the occasional sideways hop. However, I have seen him do a short run along the cubby-hole in panic. Only rarely though.

How can we explain the weirdness going on with this Grunt? I don't know, and it's quite frustrating, but here's some speculation.

Consider first the floating death anomaly; FDA for short. I've already pointed out that he acts in all regards as if he's falling. Those multiple aspects are enough to persuade me that he indeed became registered as 'falling', by the game. Of course, that's mysterious in itself and we can wonder how fall initiation occurred. Could it perhaps be do with him getting unusually far back in the cubby-hole?

But also, why doesn't he actually go down and settle on the ground? I wonder if that's to do with some sort of layer of coding designed to keep the Grunt in the cubby-hole, perhaps as an ad-hoc failsafe measure.

Since the FDA eventually settles into the swimming phenomenon, I have a suspicion that the phenomenon itself, as occurring outside the FDA (either by killing the Grunt or blasting his settled body), is likewise linked with the business of fall initiation. I conjecture that whenever the Grunt is swimming, he's actually registered as 'falling' (and as such, his body is being animated just the same as it would with any dead Grunt falling through the air).

A bit of supporting evidence is how, when you tag a swimming Grunt, there's a downwards streamer. With frozen personnel, streamers indicate the potential direction of motion. This suggests that the game considers the swimming Grunt to be heading down (potentially or otherwise), which is in line with falling of course.

Thus far I haven't addressed the business of the 'strange settling' and 'body-lifting weirdness' mentioned in the previous section, but those phenomena might provide clues to help guide us to an overall explanation of what's going on. Alas however, this so far evades me.

While playing around with a sniper rifle I realised I could quite easily get the Grunt 'twitching'. That's the term I use for when an NPC alternates back and forth between two poses from frame to frame, producing a flickering effect. It seems to be linked with the NPC looking up or down, and I've seen it in various situations, including with the hidden thirsty Grunt of level 10. However, I've never been able to produce it as easily as with this Grunt.

You can see the method demonstrated in BCM693, starting at 2:14. Typically, getting the twitching takes no more than a handful of tries. Note that you should do it with flashlight off, otherwise any twitching will quickly end because the Grunt senses you and turns around.

I should say that although this is yet another bit of weirdness connected with the Grunt, it's quite separate from the swimming business and floating death anomaly. That's why I've left my description of it until the end of the article here.

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