I had considered dropping a lv 4 shatter spell and seeing what it would do to their platform. But that, by the rules would be useless as it's being 'carried' by the croc.
I don't think I'd enforce that worn or carried exception here.
Speaking of which, I've been having a heck of a time moving my icon around. Seven Lizardfolk, a platform, a web spell, and my original croc was made up of parts, because for some dumb reason I thought it would look better that way. It's taking me forever to futz around with the map. I've spent even longer now making a new Icon for the critter.
You see, in 5e even creatures that are, say, 120 feet long, roll up into a "fighting ball" (it kinda makes sense, actually) so that they occupy a nice square space, so that you don't have to worry about facing. I tried to make my croc all long so that it looked cool, but it's making it hard for me to tell where it "occupies". So I made a new square one, occupying it's "official" gargantuan-size space.
Trouble is, then it was lost under everything that's on top of it. SOOOO... It also has a 10' reach, so I grew the icon out to its reach size. Of course, then I'm back to being a little confused by what it actually occupies. SOOOO... I made a square in the middle, which is it's actual by-the-rules-gargantuan-space. The rest is it's reach. (This is why you'll see Lorenn within the croc's space - though he'll be there anyway if he gets swallowed!)
I'll keep working on it... hang in there. Almost there.