Boss Reptilian (as named internally) is an intense boss battle theme in Metroid Prime 3: Corruption. There are two versions of the theme. The first, Boss Reptilian, is heard during battles with multiple Reptilicus Hunters in the Grand Court and Hangar Bay rooms, a group of Warp Hounds in Gel Processing Site, and the Korakk Beast.
The second version - internally titled Boss Reptilian2 - is used for the battle with the Defense Drone. This version is slightly different as it has more prominent percussion, including many of the same instruments from the Omega Pirate's theme. It also includes a more intense, orchestrated portion that the other version lacks. The original Reptilicus Hunter, Warp Hound and Korakk Beast version was altered for the Metroid Prime Trilogy re-release of Corruption to include the percussion of the Defense Drone's theme, but not the orchestrated portion.