This is gripping stuff btw.
I used to have a colleague who would "borrow" i.e. steal people's clothes if she felt cold. Which was every day as she would come to work wearing short skirts, a vest and nowt else - not that I care what she wore, but it clearly wasn't going to keep her toasty. Pop to the toilet or to another office and you would come back to find your dickhead colleague wearing your jumper, cardi, scarf or coat. And then when you confronted her on it, she would giggle in a way she probably imagined was cute and REFUSE TO GIVE IT BACK.
Only recourse was to stand over her, glaring and say "I'm just going to wait here until you give me back my [whatever]" at which point she would eventually look at you like you were some kind of massive fun hater and remove it. But only I very few people had the nerve, and most would just sit there, freezing themselves, looking sad.
She used to pinch people's stuff without asking as well, things like lipbalm, and just leave them on her own desk or in her drawer. The infuriating thing was apart from everything about her if she'd just asked to borrow things, we'd probably have said yes! But to her that wasn't part of the "fun". 
Can't believe that bowl story earlier! Poor you.