Derrick is one of Francine's relations at a family reunion in "Family Plan".
When Francine decides she wants to be part of a larger family, she acquires the phone number from the Langley Adoption Agency and is invited by her wealthy father, Nicholas Dawson, to a family reunion. There, she and her own family finds that they are not welcomed by all, with Francine considered by Cousin Janet to be a gold digger, and Steve, making macaroni art with the other kids, butts heads with Derrick. He eats what he believes is a picture of Derek's mom done in macaroni to show him up, but Derrick pulls out a large penis done in pasta which Steve reluctantly starts to eat as well.
When her own family leaves her behind for ignoring them, Nicholas blows his top at everyone using their own phone data plans instead of the home network and institutes a fight to the death among his heirs with the sole survivor getting the family fortune. As Francine tries to stay alive, she remembers that she isn't on the family account, but when she tries to call Stan, her phone is snatched by Derrick who takes off with it. As he plays games in a tree, Stan gets a notice that Francine's phone is approaching its data limit. Stan calls and nearly exposes Derrick, who gets the drop on his would-be killer first. Answering, he informs Stan that Francine has probably been killed and they frantically return to the mansion. Francine and Janet's bloody bodies are thrown onto a pile of remains by the sole survivor, joining Derrick's which is seen with several knives and swords sticking out of it.
Derrick is voiced by Colin Ford.