You know who also can't get over that they're on the moon?

"We're eatin' cake on the moon!"

This guy.

Fitting the location, Joker's eyes practically have stars in his eyes even as he's a little busy balancing a plate on his knee so that he can use his good hand to eat. But what's a little trouble in exchange for eating cake on the moon?

"Just when I think this place can't surprise us anymore, Jimmy!"