He first appeared in "Anti-Poof". After Anti-Cosmo was complaining that Poof didn't have an anti-fairy, he noticed that Anti-Wanda was pregnant with an "anti-baby". Soon after Foop's birth, he decided to wanted to destroy Poof so he could be the only fairy baby in existence. He then proceeded to drain both Fairy World and Anti-Fairy World of their power in order to send Earth into chaos. However, having not recieved a nap that day, Poof and the other fairies and anti-fairies managed to get Foop to fall asleep.
He is the only anti-fairy to not have his name just be the same as their fairy counterpart with "Anti" added to it.