Disasterstroke
When a sudden flash of inspiration leads to a horrible chain of events. The opposite of a masterstroke.
Jim: I thought it might be a good idea to use a blowtorch to trim my butt hair. Now I haven't sat down for a week and when I fart it smells like barbecue.
Bob: That's a hell of a disasterstroke dude
Bob: That's a hell of a disasterstroke dude