Homers were a strain of zombies so stupid it was considered almost a waste of ammunition to actually kill one.
10 years after the events of Zombieland, new varieties of zombies have been introduced in Zombieland: Double Tap. Named after the titular Homer Simpson for their idiocy, the "Homer" variety had no special advantages and were actually considerably less of a threat than most rank and file zombies. However, they can still infect people and will attack if they aren't distracted.
Homers have been seen getting their tongues stuck to frozen statuary, chasing butterflies or other shiny objects, and walking right off the edge of a tower to their deaths.