Support toy, as his mother calls it.
Most suspect a blanket or a stuffed bear or similar.
This kid? Batman. It’s a Batman action figure.
Can’t sleep without it. Needs to have it with him to eat. Holds it during car rides. He feeds Batman some of his lunch.
It gets misplaced a lot. So his mom usually says “Batman is fighting crime” when he asks where Batman is. Doesn’t usually work to settle him down, but sometimes it does.
It’s hilarious.