Mushroom Boi!

The Mushroom Boi! is a power skill which summons a friendly Jerkshroom. It was introduced with the Bad Seed DLC. It will follow the player around and attack any enemy directly in front or behind its line of sight.

The Sacrifice
The Mushroom Boi is part of a sacrificial ritual that grants the player the Sacrificial Outfit. To initiate this ritual, the player must go to the Morass of the Banished. In it, the player must reach the end of the biome, where a masked individual known as the Swamp Priest resides. The Swamp Priest stands next to an altar that depicts Mama Tick, he nags the player to offer a sacrifice, namely the Mushroom Boi. If the player complies, the Mushroom Boi is completely removed from the player's inventory and the subsequent fight that should take place in the Nest will not occur. This ritual can be repeated in subsequent visits with the same result, but the outfit can only be obtained the first time unless the player did not hand it in to the Collector.

If the player has a ranged weapon in their inventory, and manages to attack Mama Tick in the brief moments she raises her eye above the water, the fight will be initiated and the outfit blueprint will not be dropped.

Trivia

 * The Mushroom Boi! is the second pet skill to be added into the game, with the first being the Great Owl of War.
 * Mushroom Boi! is the only item required to obtain a blueprint of an outfit.
 * It is also the only skill to have achievements associated with it.