Mythic
From Halopedia, the Halo wiki
Mythic, often shortened as LASO for "Legendary with all Skulls On", is a "fan-made" difficulty for the Halo series. In order to play on this difficulty, the game needs to be set to Legendary and all the Skulls activated. Mythic is possible in Halo 2, Halo 3, Halo 3: ODST, Halo: Reach and Halo: Combat Evolved Anniversary. When played solo, its shortened name is "SLASO"[1]. Halo: Reach weekly challenges often include a challenge in which the player needs to complete a certain campaign level. Although it can be beaten, the game stats will still read "Legendary" since Mythic does not exist in the game's code. For the same reason, the difficulty does not have an icon like the official ones.
