The equivalent of an ambulance, but instead of sick people, a dumbulance carries dumb people away.
Dumbulance originates from the TV Series, Trailer Park Boys, in an episode in which half-witted Corey and Trevor are shot at, and when they plead for an ambulance, an angry Ricky retorts that they ought to instead be picked up by the dumbulance.
when a person who is usually not smart or makes dumb decisions happens to do something that everyone assumes is stupid, somehow pays off or is very successful at the end
rev. smartdumb
yo J just found a bag of $5000 cash. He bout to take it to the police station.
3 days later.....
yo J returned the money and the owner let him keep it and gave him an extra $5000.