About a year ago I stumbled upon this hilarious comic strip that I thought, at the time, belonged to XKCD. In one "slide" (can't remember the technical name in regards to comic strips) a boy comes home from school looking depressed. Then father asked what happened. Then the boy says someone crapped in his lunch bag. The last slide is the father laughing hysterically (for he was the perpetrator).
I can't find this slide, and apparently it isn't XKCD's (my brother and I have exhausted their archives). Anyone know what I'm talking about?