The Ferals are a group of one-time villains from the classic Cartoon Network series, My Gym Partner's a Monkey, only appearing in the episode "My Feral Lyon". They are a gang of three deranged alley cats, who steal stuff from everybody they talk to. They are a group of greasers, who act like Fonzie from Happy Days.
The leader is voiced by Tom Kenny, the second member is voiced by Nika Futterman, and the third member is voiced by Grey DeLisle.
In "My Feral Lyon", Adam and Jake first discovered The Ferals, when they saw them dismantling Principal Pixiefrog's car. Jake, in need of a leather jacket begged Adam to join their group and get a leather jacket for him. Jake couldn't do it himself, because he didn't qualify as a cat, so he told Adam to play the "Lion" card. Despite the school's numerous warnings and Coach Gills' PSAs, telling him never to talk to feral cats, at the expense that he'd be robbed blind, Adam went up to them, to help his friend out.
As soon as Adam first interacted with The Ferals, they instantly got him blamed for tearing apart Pixiefrog's car. Luckily, the person who caught him was the apathetic Mrs. Warthog, who was completely fine with him destroying the belongings of his superior. The Ferals were amazed at Adam's ways with authorities and decided that it'd actually be a good idea to let him into their group.
The Ferals first told Adam that before they'd let him in and give him a leather jacket, he needed to pass "initiation". The initiation was just a series of events, where The Ferals caused a bunch of crimes on the school premises, and blamed it on Adam. First, The Feral took Adam's clothes and dressed up as him, so they could get into the school. This led to Adam being left out of the school, because he was naked.
Later in the library, The Ferals made Adam run around in his underwear, singing "I Wanna be an Airborne Ranger!", distracting the librarian, while they stole all the books. The Ferals lied to Adam, saying they'd simply be returning overdue library books, so they could get on his good side. Adam later stood guard by the Teacher's Lounge, while they continued to rob the school. Jake came up to Adam and told him he could call off the plan if he wanted, cuz he already traded the Ferals his truck for a leather jacket. Jake explained that they needed to truck to quote on quote "move some junk". It was at this point, Adam realized what was going on.
Adam and Jake saw The Ferals loading all of their stolen items into the truck, which even included various students for some reason. Mrs. Warthog, as usual, was doing absolutely nothing to stop them. Adam took matters into his own hands and tied Jake's stretchy leather chaps to the back of their truck and attached it to the school, so that when they drove off, the elastic pants would pull back on their truck and slingshot them back into the school. They then crashed into Principal Pixiefrog's office and were knocked out cold, where they were promptly punished for what they did.
Unfortunately, things had already gone too far before Adam and Jake stopped them, since they should have never even spoken to the Feral cats in the first place. Because of this, the entire school had to sit through another PSA from Coach Gills, explaining to them the dangers of feral cats.
Their attire and mannerisms parody that of Fonzie from the 1970's sit-com, Happy Days.
The leader's name is Feral Cat A.O., which was only listed in the credits.
His initials are a pun on the common phrases "Ayyy" and "Ohhh", uttered by Fonzie in Happy Days.