A monk asked Joshu, "Does a dog have the Buddha nature?" Joshu retorted, "Mu!"
http://www.catb.org/~esr/jargon/html/M/mu.html
Thank you (I feel like I just got hit by the proverbial monk)
Is Joshu a cow?
Knock, knock.
-
- Who's there?
Interrupting Buddhist.
-
- Interrupting Buddhi...?
Mu!
See also
MuAnswer.