Psychonauts

Story Related, cannot be missed.

After beating the Lungfishopolis area, Linda will take you to the final island of the game. Here you will find a security guard who is also a conspiracy theorist: delve into his mind to start the Milkman Conspiracy level. In this level you will use various disguises found throughout the level to avoid and blend in with the "G-Men" scattered about the level. Once you discover the "truth" about the Rainbow Squirts and their relation to the Milkman, you will engage in a boss battle with the Den Mother so defeat her to unlock this trophy.

Boss Tips: This boss plays out a bit differently than the bosses you've faced before. When the boss starts she will have two attacks: throw a box of cookies at you and throwing a pin at you. After she throws the box, she will yell before throwing a pin at you. You have to throw the box of cookies at her using Telekinesis to damage her before she throws the pin at you or you can run up close to her and use Marksmanship. After taking half damage, the room will go dark and you must use Clairvoyance to see from her perspective. The same pattern still applies but it's more difficult to aim at the cookies at her since you technically can't see where she is. I would suggest using Marksmanship for this phase of the fight.