I'm hoping it's just a prank by one of the other students- oh, we're at Hogwarts by the way, just so you know.

[Gets out of bed and notices Tony's PJ bottoms, shaking his head and getting his wand.]

First though, we need to find something for you to wear... I think my friend won't mind us using his stuff. [Rifles through Tony's drawers and gets an AC/DC t-shirt and jeans out. On after-thought, gets one of Tony's clean underpants out as well.]

Here, put these on and I'll shrink them down for you.