I've just noticed something, watching a video of all Things being used. The three Ice-based Things produce the same background and effects, except for this:
The regular-sized one - Shaved Ice - has one penguin on the right. The big one - Air Conditioner - has two penguins. And the mega one - Fridge - has three!
In all the animations, the penguins watch the Thing drop into view; their heads follow the object's movement. It's a subtle difference I'd probably never have noticed unless I'd seen them back-to-back!
My Pre-Hooktail Pit Run of Paper Mario: TTYD without Mega Rush P! Playlist: http://www.youtube.com/playlist?list=PL5045EE00B4B9581F