Humanoid easter egg
From Halopedia, the Halo wiki
This is on the level Sierra 117. First get to the part where you encounter the Jackals with Carbines. Near one of the Jackals will be a group of humanoid creatures. You may need to look around a little. They aren't alive, but if shot they will bleed.
File:1931110-Full.jpg
Does this face look familiar?
