Eat my potatoes - Eating someone's potatoes is the worst thing you can do to s

Eating someone's potatoes is the worst thing you can do to someone, and it means you're the toughest and they're the weakest.

I ate my cousin's potatoes and he cried like a baby.

He ate my potatoes because I didn't want to play with him.

I ate my friend's potatoes and now he won't talk to me.