Ultralisks are by far the most dangerous of the common enemies. They have high hitpoints, extremely high attack damage (280 base), and fairly fast, cleaving attacks. Additionally, Ultralisks can burrow and charge forward, knocking back nearby CP forces on arrival. Their damage is so high that in most cases the only effective way to fight them is to kite back. Ultralisks come in three strains: Base, Noxious, and Primal.
Primal Ultralisks are situationally more threatening than their normal brothers. They have higher movement speed and hitpoints, but cannot burrow, have smaller collision boxes. The movement speed makes it more difficult for heroes to kite away. They generally spawn from Ultralisk Caverns in pairs once every minute.
Noxious Ultralisks are by far the most dangerous normal enemy. They have much more hitpoints than normal Ultralisks and emit a poisonous, slowing aura of Noxious Cloud similar to that of the Brain Bug'sToxic Gas. A single Noxious Ultralisk can kill an entire CP infantry battalion in the blink of an eye and its mech backup seconds later. They most commonly spawn from larval Eggs near Hives or when Lairs or Hives are destroyed.