Utility Mobs- Utility mobs are created by and serve the player.
Snow Golem Snow Golems are the game's first Utility Mob, which Notch defines as any player created Mob. They are friendly to their creator. Snow Golems are created using pumpkins and snow blocks, and will throw snowballs at enemy Mobs. As Snow Golems move, they leave a trail of snow on the ground, except in Plains, Beaches, Swamps, Mushroom Island, Desert, and Jungle Biomes, and The Nether. If a Snow Golem walks over a mushroom, the mushroom will be destroyed and dropped as an item. Snow Golems do not take fall damage. Once killed, the Snow Golem will drop a maximum of 15 snowballs. Like Endermen, Snow Golems take damage upon contact with water.
Iron Golem Iron Golems are large, strong Utility Mobs. Their main purpose is to defend Villagers in NPC Villages from hostile mobs and siege attacks.
Boss Mobs- Boss mobs have more complicated attack patterns and movements. They also have a large amount of health. Boss mobs only spawn once per world.
The Ender Dragon The Ender Dragon is the first official Boss Mob to appear in Minecraft. It only naturally spawns in The End. This mob uses the Dragon model Notch created, but utilizes a texture more like an Enderman, being black and scaly with purple eyes.