The Sign Zombies (also referred to as Evil Sign Posts by Finn) made their first appearance in "Tree Trunks." The Sign Zombies were first seen in the episode when Tree Trunks went off on her own while following a Skeleton Butterfly. When Finn and Jake found her, she was surrounded by Sign Zombies. Tree Trunks, who did not recognize their evil nature, had naively started a picnic for the Zombies, however not soon after, the Sign Zombies were distracted by Finn and Jake, breaking out a fight with them. During the fight, Finn tried to protect Tree Trunks by huddling over her, giving the Sign Zombies the chance to scratch him. The fight ended when Jake jumped on top of Finn, turned into a giant ball and began rolling into from the Sign Zombies, knocking them away. The Sign Zombies are located in the Evil Forest. Sign Zombies also make an appearance in the Nintendo DS/3DS game Adventure Time: Hey Ice King! Why'd you steal our garbage?!! as a recurring enemy.
Each Sign Zombie has a different appearance, with each of them having a different sign on the back of their heads. Their main appearance consists of a worn down signpost, with dark wooden arms and legs attached. They have mean-looking faces with sharp teeth. Their arms and legs don't show clearly until they start moving, making the appearance of a normal sign a camouflage of sorts.
Known Sign Zombies
The following Sign Zombies are seen in "Tree Trunks":