Phenomenon in which any animal caught defacating on my lawn bursts into flames, and it wasn't my fault.
Bob: "Howdy neighbor! By any chance, have you seen my sweet little Sparky? He's been missing for two days now."

Jeffy: "Uhhh....uhhhhh....I didn't do it."

Bob: "What?"

Jeffy: "You're not gonna believe this: I was mowing my lawn the other day and...I smelled something...burning. I looked over to see poor Sparky engulfed in a ball of fire, yelping for help......but by the time I reached him he was utterly consumed and only his ashes remained. That's what happened to Sparky. I'm not lying, it was Spontanious Animal Combustion Bob."

Bob: ".............*gurgles*"
by Jeffy the Retarded Beaver August 15, 2007
Get the Spontanious Animal Combustion mug.