Skulltaker Halo 2: Famine
From Halopedia, the Halo wiki
Skulltaker Halo 2: Famine is an achievement in Halo: The Master Chief Collection. It is awarded for collecting the Famine skull in Halo 2: Anniversary on The Oracle while playing on Legendary difficulty. The achievement is worth 5 Gamerscore, and the Xbox achievement art is a still from the Halo 2: Anniversary ending cutscene for Gravemind, depicting Tartarus crushing a pod infector with the Fist of Rukt.
Location
After you get off of the slowly descending elevator, you will come to a hallway where you see a handful of dead bodies. Continue into the next room, and you will be on the second floor of a room that has a lot of glass windows. When you enter this room, look to the right, and find the third pane of glass. It should be to the right of a wall that has some Flood guts splattered on it. Shoot out this window, and the windows directly across the room. If you look below you, you will see a platform that has four tall posts. On the far side of the room there is a column that is right in between the two windows on the far side of the room. Turn on your Active Camouflage, and jump to the center platform. Jump on either of the posts on the far side of the platform and jump to the column between the windows. Make another jump through the window you shot out, and make a left. Walk all the way to the end and you'll find four Elite Combat Forms convulsing on the floor, with the Famine Skull in the middle of them. Sometimes, the Combat Form nearest to the battlefield stands up, but it does not attack.
