Ice Bulls are seen in "What is Life?" and "Princess Monster Wife." They guard the Ice King's castle and chase intruders. In "What is Life?" one chases Finn and Neptr down a tunnel and runs into a door shaped like lightning bolt, which causes the bull to shatter and spill its organs. It is possible that the Ice Bull is summoned by the Ice Toads' alarm. In "Princess Monster Wife" a small herd of them is seen running through a large section of Ice King's castle. It is the only ice monster shown with organs.
Ice Bulls are bull-shaped creatures made partially of ice. They have small, round, white eyes, and their organs are visible inside of them, through the translucent ice that makes up most of their bodies. Ice Bulls have what appears to be a small brain and a basic nervous system, in addition to their digestive tract.
- Ice King uses Ice Bulls as guard animals. Another guard creature is the Ice-o-pede, which is made purely of ice.
- Their mouths look similar to Flambo's mouth when he is casting the flame shield spell.
- This creature also appears as an enemy in Adventure Time: Hey Ice King! Why'd you steal our garbage?!! They have 25 hit points.
- They also appear in a book: "Adventure Time Which Way Dude? Jake Goes Bananas #2"