LOL
I think you're actually right, I might have been thinking of a sea cucumber but I just didn't register it hahaha
The way the art thought process went was: they need a way of looking like they can walk on spikes (regular legs wouldn't cut it, wavy slime it is!) -> they need to look strong and like a platform (give 'em a good ol' turtle shell) -> wait how do we combine these things (we.. just.. do???)
And then a teammate called it a turtle and it stuck ahaha