Invader ZIM Easter Egg - Sanguine the Vampire in Invader Zim

In the Invader Zim episode "Plague of Babies" When the lady is leading Zim to the baby, if you look in the background you can see a picture of a strange big headed thing with huge fangs. This is from one of Jhonen Vasques' "Johnny the Homicidal Maniac" comics, issue #7. Its a mini comic about a goth named Eric who gets turned into a vampire.