Great Unmasking is a skill first featured within Fossil Fighters that is unique to Guan (DS). This skill allows Guan to transform into T-Rex (DS). The resulting T-Rex will be at the same level as the Guan performing the move. This move also restores all lost HP. During the third Rank-Up Battle to become a master fighter, Saurhead has a Guan that will use this move if not stopped.