Temporary Profile
From Halopedia, the Halo wiki
A temporary profile is used in Halo 2 and Halo 3, for players or users that have not created a profile and wish to play the Multiplayer or the Campaign. When a player without a profile signs into a game, he or she will be asked if they would like the use a temporary profile.
Temporary profiles cannot be saved (and cannot achieve any achievements in Halo 3). When you receive a temporary profile, you are issued a random username and tag. Examples are "Devious" and "Sparty".
