Just addressing the first pics - the blue ones.
I think it looks like an air mattress or pool raft.
Could someone have inflated one with helium and let it go? Would it float like a balloon? Seems like it would.
Well, it sure looks an awful lot like a matchbox car my son lost back in the early 80’s... I always wondered where that car went.
That’s a good idea! I am thinking one of those inflatable kitty pools.