Comic Jail is where all the bad comic strip characters go. Rat was sent there. there once.
"Ya' hear that guys? Looks like the Rat here won't give Jeffy his smokes."
-Jeffy talking in the third person about Rat.
When Rat went to jail, he saw Dennis (Dennis the Menace), Sarge (Beetle Bailey) and Jeffy (The Family Circus). Rat refused to give Jeffy a cigarette, which angered him.