The Regenerador is a zombie-like humanoid B.O.W. that appears on the island stronghold of Los Illuminados in Resident Evil 4. Created by introducing several leech-like Plagas into human test subjects, the result of the Illuminados' experimentation is a vaguely human-looking creature covered in hairless, rough grey skin with a perpetually grinning mouth filled with sharp fangs.
These creatures are named Regeneradores due to their artificially accelerated metabolism which allows them to almost instantly heal any wounds. When a Regenerador is wounded, a number of tiny tentacles (presumably those of the Plaga) appear within the wound and 'knit' new flesh, rapidly healing the injury. Even if a limb is severed or the head is destroyed, the Plagas can reconstruct the damaged tissue and the Regenerador will be no worse for wear.
When a Regenerador attacks, it usually does so by mauling or biting opponents. Regeneradores normally move slowly, but are capable of spontaneous bursts of speed when attacking. Their malleable bodies allow them to stretch their limbs to great lengths so that they can grasp a victim from far away. When prey is nearby, they are utterly relentless and will advance towards their target regardless of what damage they receive. Even shooting a Regenerador's legs off won't stop it as it will continue to crawl or even just flop its way towards its prey. While it hardly moves gracefully when completely amputated, this B.O.W. can still propel itself forward with startling speed.
It is easy to tell when a Regenerador is nearby; these creatures have strained and erratic breathing which sounds like an agonised hissing sound.
Killing a Regenerador requires calmness and precision. While it is possible to kill one with continuous weapons fire, such a tactic will rapidly deplete ammo. Regeneradores can be destroyed by killing the Plaga parasites within their bodies; however, specific equipment is required to detect the parasites. A sniper rifle equipped with an infrared scope is the best tool for dispatching these monsters. Regeneradores have very low body heat but the Plagas within their bodies can be easily identified through an infrared scope. Targeting and destroying the parasites individually will save ammunition and kill the Regenerador much more quickly. Without the Plaga, a Regenerador's body chemistry will destabilize and its own super-metabolism will destroy it from the inside out. Regeneradores explode upon death, so distance is strongly advised at all times.
See also: Iron Maiden.