In the Pillar of Autumn opening cutscene in Halo: Combat Evolved
Anniversary, various faces can be seen on one of the keyboards.
Also on Halo: Combat Evolved Anniversary, there is a notice board with various
still/ stupid things on it, with one of them being the Trollface.
In Halo 3, on the mission Sierra 117, a family of Monkeys can be found in the
cliffside. They all appear to be wearing masks, with the largest one holding a
teddybear. Their purpose is unknown.
In Halo 3: ODST, one of the Monkey Men return. This time, Gunnery
Sergeant Buck can be found picking bugs out of the Monkey Man' s hair.
To find this, you must beat the game on Legendary, and pan your
thumbsticks to the left during the final cutscene.
In Halo B, on the last mission, if one goes astray of the linear set path, a
cardboard cutout of a Jason Jones (A Bungie Developer) can be
found floating about in a corner.