A lot of crazy stuff happens in Deadpool 2. A lot. But perhaps nothing quite matches the ‘baby legs’ moment. It’s when Wade Wilson aka Deadpool (Ryan Reynolds) is stuck on the couch of his elderly blind roommate Blind Al (Leslie Uggams) while his legs re-generate, having been earlier torn in half by Juggernaut (oh yeah, that was pretty crazy, too).

We first see the stumpy legs – and possibly more – as Wilson sits. Then, Cable (Josh Brolin) arrives and Wade shuffles up to him, baby-walk style. To pull off the legs gag, director David Leitch entrusted production visual effects supervisor Dan Glass and VFX studio Double Negative to work their magic. vfxblog asked Glass to describe how those shots were made.

Dan Glass: It was definitely a creative challenge in, mostly, trying to gauge how to represent it, and how far to go, so to speak. I think luckily the actual technique of how to shoot it we arrived at very quickly, and ended up being the simplest. We thought about making a hole in the couch so Ryan could kneel and we’d just add legs onto the front of him. But, in working it through with Ryan and David, it affected his body language too much, and he wanted to be able to almost suggest some of the performances of the legs, so he just sat with his real legs forward with tracking markers on them. For the couch scene, he sat legs crossed, keeping his legs low so he didn’t cross his upper torso too much.

A lot of the poses and the variety of poses were actually something that came up later. We, with the team at DNEG, visual effects supervisor Mike Brazelton and his crew, they could produce the whole range of different ideas that we talked through with Ryan and David, and they picked and said, okay, we should have a different pose each time we cut to him, because it’s funny, and they should be these poses that are almost a combination of adult poses with childlike legs or childish poses that look funny on a full grown man.

For how he then walks across, we decided to try a version of it, like, what if someone is walking on their knees? Does that give us about the right height? And luckily, with a quick mocap test that DNEG did, it quickly showed that that was going to work, but we just needed to pay attention to how Ryan moved as he walked on his knees across the carpet. And that he needed to be aware not to sink backward or lean too far forward, which you can do more of if you’ve got the weight of your lower legs behind you.

So, we guided him to keep his upper torso relatively straight and to throw his hips forward so that – the natural muscles in his lower legs are not quite strong enough to support him. So, we said, look, try to throw your whole weight forward, so that when we put the legs in it will look more convincing. And he did a great job of taking that on.

And then the final thing was, the look of the legs themselves. We did try and concept some variations that were more weird, almost fetal and alien-like limbs, more like the hand that appears in the first movie. But it felt quickly that that got a little too gross and unappealing. In the script dialogue from early on, although you obviously have Domino and Weasel’s reactions, which are fairly repulsed, Domino, of course, comes in and says, ‘No, I’m talking about your face. Your legs are cute.’

And so, that gives us a clue as to what the intent of the writers was. I think the idea of bringing them to be more recognisably human and – although, it’s sort of a controversial discussion, or at least it felt like it was always going to be a slightly odd and difficult thing to pull off. But, actually being more normal with it, I think, it helps the humour and helps you concentrate on the humour of the scene and not be so horrified or appalled at what’s going on below.

So they’re CG legs. We could have gone with another approach as well, to get somebody as a stand-in and then just stick them onto Ryan. But I think we needed the control. And, actually, there are subtleties in the way that Ryan was moving his head, even when he’s on the couch, that might have been – I think they would have been hard to reproduce with somebody fitting into that. And the walk across the room, those had to be CG to line up with him walking.

Keep an eye out for more pieces from me on Deadpool 2 in other publications.