Absolutely.  My daughter is 8 now but when she was a toddler we did a Gymboree type class that had this.  A ham got stuck in there then too.    The thing is, it IS kind of hard to get out of, even if you're not a planet because you've kind of got to dig your way out and there's not really a place to brace yourself for leverage.  But you know what?  My 110 lb ass doesn't go in there.   I'd feel really silly waiting in line with little kids to do a child's thing.  Maybe that's just me, but I wouldn't dream of doing that if I were a ham. Nobody wants to see that.