Brainpan Achievement in Halo: The Master Chief Collection

Similar to the hidden skulls found in the main Halo 3 Campaign, these collectibles make their return to six of the Halo 3 Multiplayer Maps: Assembly, Orbital, Sandbox, Citadel, Heretic, and Longshore. Once again, these skull collectibles are extremely well-hidden and come in the appearance of an actual human skull.

Unlike the Campaign skulls however, these Multiplayer skulls do not act as additional gameplay modifiers. Instead, their only reward is the achievement. Despite this, make sure to utilize the video below in order to locate all six Multiplayer skulls and this achievement, as well as the six that precede it, will unlock without issue.