It's the one with frosting around their mouth.

Wow don't you live with some assholes,but easy way to find out who's doing it go get some chocolate ex-lax and make frosting put it on the cupcakes and leave them out and let the fun begin 🤣😈 O ya the most important thing is to make sure there's no toilet paper too 😇

Came here to say exactly this.

I know you're probably joking, but I believe intentionally tampering with people's food is illegal in a lot of places. However, if you label them as your food and they still eat them. Well, that's not your fault. ;) I am not a lawyer though, so double check before you take my word for it.

You are correct tampering with food is illegal and can get the person assault & battery charges.

Tampering with someone ELSE'S food is Illegal. Tampering with your own, not so much. And you can do it in a way that could be played off as your own personal tastes, like adding some extremely hot ghost pepper sauce into the frosting. They can't prove you don't just like your cupcakes spicy.

just how many house mates do you have?

Plot twist: OP lives alone.

Just tell them they are made of breast milk or someones dried placenta

You should go around licking your housemates and the one who’s into it is your culprit.

Maybe it's like Murder On the Orient Express. They all did it.

“Brendan hahahahah” I stalk