The Vegans are the primary antagonists of "Vegans", the eighth season two episode of the animated adult swim show "Mr. Pickles".
A redheaded woman drops by the Goodman household one day and proudly proclaims to the mother, Beverly, that she is a vegan. Having raised the housewife's curiosity, the redhead invites her to the "Vegan Headquarters" which just happens to be a cult devoted to the dietary practice.
Ever eager to join, Beverly nevertheless fails to grasp the concept and continues to infuriate the vegans, their leader in particular, with her desire to continue eating meat. The point comes where the cultists cannot take it anymore and decide to kill Beverly by ritualistically bludgeoning her to death with hammers. This process is halted when a pizza boy shows up with an all-meat pizza that Beverly had ordered. All but the leader rush to eat the unexpected and wonderful-smelling food and immediately begin fighting over it. Seeing Mr. Pickles standing there, the redhead even kicks him in the face, yelling at him "Back off, you filthy animal!"
Knowing that his moment has finally arrived, Mr. Pickles slaughters every member of the cult and rescues the naive-as-ever Beverly from their clutches.