mad c
A mad c is when someone does something so wild or so lame it makes you laugh or cry. They're your best friend, so you can't hate them even if they're the worst.
You: "He tried to sing and it sounded like a cat was being tortured." Me: "That's a mad c."
You: "She jumped into a pool full of jellyfish." Me: "That's a mad c."
You: "He tried to ride a bike with no wheels." Me: "That's a mad c."