I'm the Secret Sandwich Swapper

So here's my secret weapon at lunchtime. I sneak around swapping out my friends' sandwiches with snacks they hate but think are from their mom or dad. Like, if Alex got a ham sandwich, I switch it for a carrot stick or maybe a weird pickle! And when Mia gets some fruit, she ends up with a pack of raisins instead. It's pretty funny seeing them take bites and make faces. Is this just my thing, or do other people do this too? Am I the only lunchtime prankster out there?