A person who is going to beat someone else may be serving them a tray of fail muffins. Or perhaps just one fail muffin. It depends on the size of the fail.
Or, it usually is used to describe something that really sucks.
You might tell someone to eat a fail muffin if they do something dumb. Or, you know, fail.
"Haha yeah, I hate Bio."
"...eat a fail muffin dude.."
"I'm gonna beat you so bad"
"No way man! I'm gonna serve you a fail muffin!"
a pet name for some1 u think is cuter than a muffin with googly eyes but wold fail at being a muffin because they are too awesome and actively human-esque...
Elena: oh right, ur my little failmuffin!
Elena: *does an epic flip*
Maeve: ohhhh rite FAILMUFFIN!!! YAY not fail :) :) :)
Tom: awww ur my little failmuffin!
Katie: awwww thnx! ur my little epic-love