Mutant Leaper id the third stage of infection as the virus continues to mutate its host all human traits vanish. They become more animistic in nature. As this stage finalize the person/mutant is unable to use weapons and equipment as the virus strength boasts. This Mutant has increased jump and dodge skill, but his damage is low. Leaper can be detected by moans and growling, this mutant also flanks player so others (mutants) can deal more damage.
Most traits of their human physical form disappear, they also gain the ability to climb walls making them tricky to shoot.