New kitten!
We have to lock him in a giant dog cage for now until he's a bit older, of course we let him out and run around if there's supervision! But he can't really explore as much as he wants, or else he might end up in a hole in the wall of that room that will make him impossible to get out of!
So that's the only reason he's caged, when no one's able to keep an eye on him or we're about to leave.