Pearls Before Swine by Stephan Pastis for May 15, 2002
May 14, 2002
May 16, 2002
Transcript:
"Did you hear that I'm pregnant again, Pig?" "You must be having a cow." "No, I'm quite calm."
“Having a cow” is an idiom for being upset and the character is a pregnant cow, so it is going to give birth to a cow. It is a pun.