Evil Ren is the evil counterpart of Ren and an antagonist from The Ren & Stimpy Show. He is the villain from the episode, "Ren's Bitter Half".
He was split from Ren by Stimpy's genetic formula. With his opposite half, Indifferent Ren, he bullies Stimpy and indifferent Ren. At the end, he marries his wife, Hideously Evil Ren, who was split from him by the genetic formula.