The wish a person makes, usually
the first thing they think of, then blurt out, when they catch a
leprechaun.
Almost always a terrible idea. Also applicable to other wish granters and devices, like genies, stars, and wishbones.
"I caught a
leprechaun and wished I never had to go to
the dentist again, so now I have no teeth... what a wishfart."
"I wished I had a
million bucks."
"You're rich!"
"No. I have a million male deer. Any idea where I can store them?"
"What a wishfart."