Oh! I didn't know about the number!
Here's a list from the creator. I'm not sure if they're all always there:
"Here is the semi-official list of symbols, more or less in order of frequency of use: eyeball, piece of pie, alien, dynamite, K2, upside-down bird, bunny head, crown, single shoe, arrow in the back.
They began in 1996 when I decided out of boredom to draw a little bird sitting on a shelf where it didn’t really belong"
Did you know that every Bizarro comic has a hidden eyeball (bottom right), alien (top right) and piece of pie (can't find it in this one)?
And always disconnect while you're in the middle of speaking.
You know the difference between a porcupine and a BMW?
Porcupines have the pricks on the outside.
Is the floor open for questions?
Ever went over a friend’s house to eat
And the food just ain’t no good?
I mean the macaroni’s soggy, the peas are mushed,
And the chicken tastes like wood?
You and G.O.B. were like those biblical brothers, Gallant and, um… Goofuth.
If I’m ever on life support, I want you to unplug me.
Then plug me back in because sometimes that works.