Fartoxic

The worst and most foul smelling fart. Also can be used as a descriptive term for something unpleasant.

Biff: "Watch out that one was fartoxic"
Jeb: *dies*

also

Zep: "Check out my ride, it is totally bitchn."
Harpo: "That thing is fartoxic bro, definitely not gonna chase any tail tonight."
Zep: *frown*