Phobos: Anomaly Reborn is a PWAD level set by Christopher Lutz released in 2003. The episode features a similar design as Lutz's other levels, with highly detailed and realistic environments. Examples of such include a moving train and a hangar with ships and transport rails. The episode was included in Doomworld's Top 100 WADs of All Time list. Thematically, the episode serves as a replacement of the first Doom episode. However, it is much more difficult than the original, with bigger puzzles and stronger enemies appearing earlier.