The Reptilicus Hunter is a specialized variant of the Reptilicus encountered on Bryyo in Metroid Prime 3: Corruption. They have been mutated by Phazon, giving them powers that normal Reptilicus don't have.
A Hunter has a much lighter skin tone and a larger, more muscular build than that of other Reptilicus. They have none of the spikes seen on the backs of the other Reptilicus; they also do not share the ability to warp, instead replacing this with ability to turn invisible. They are not hostile to the other form of Reptilicus, and utilize Warp Hounds more often than normal Reptilicus. They are also capable of scaling walls, which allows them to reach higher ledges to attack from.
Once the X-Ray Visor is collected, Samus can see the Reptilicus Hunters when they are invisible. Reptilicus Hunters are more resilient to Samus' weaponry than the standard variety. Ice Missiles will not freeze the Hunters as quickly as it would their cousins. Also, because of their resilience to heat-based attacks, the Plasma Beam's burning capability is negligible. Samus can freeze the Reptilicus Hunter as it is throwing its chakram, so the chakram comes back and shatters the frozen Hunter.