What would you do?

So basically, I made a bet with a kid at my school that I could ace a particular Calculus test. Our bet was $10, based solely on my grade, so if I got 100% on the test, I got $10, if I got anything short of 100%, I owe him $10.
We had two opportunities to take the test, and the better of the two grades would count.. I figured I could easily ace one of them since it was the exact same test (seriously).

Both tests pass, I don't ace either of them.

F me, right?

I was totally ready to cough up the $10 until my buddy *total douche + short description in next paragraph (optional to read)*

He wears fucking toms (yeah the shoes). With no socks. He's like a five year old and hits people when something doesn't go his way. He constantly makes offhand sarcastic remarks regarding anything that seems to put him on a feigned pedestal of superiority while placing you below him. He watches Disney movies in his spare time. He's going to Gonzaga. He is a hipster clusterfuck (yeah, stole that from you, Cobra Commander), only he's more like a wannabe hipster, like everyone else these days. He wears v necks. With sleeves that are too short. He likes to brag about how many bands and lyrics he knows and thinks that makes him better than everyone else around him. He sings Kesha songs in class. He sings Alladin (the Disney movie) songs in class. /description.

So anyway, I was ready to keep my end of the deal until he sees his score of like 63% and decides "I'll talk to the teacher and retake it. I went to the midnight showing of the avengers last night, so I was pretty tired"
Immediately, and obviously, I'm like "What the fu**?, if you can retake it, so can I!"
He pulls this shit like "you didn't ace it, we only had twice to take it and you didn't ace it" (all the while sounding like a 5 year old"

So now, a week later, when I think he's forgotten about it, I get a text that says
"Hey you still owe me cash"
I'm a good person, and stick to my word, despite how stupid this guy is, and so I go and scrounge up some of the dirtiest pennies I can find, along with nickels, dimes, and crumpled up some dollar bills, totaling almost $10. Guess what? I put that shit in a dirty old sock in my closet and went into class the next day and slammed it on his desk.

/rant