The franken ape, also known as the research mutant, is an enemy in The Lost Frontier. Originally silverbacks, these mutant apes were captured by the Aeropans and heavily experimented on at the abandoned research rig, thereafter encountered in the mission "Search for light eco".
Franken apes are first encountered in the mission "Search for light eco" inside the abandoned research rig. At first they pop out of vents near the ceiling, and appeared to be awoken by a nearby Precursor idol imbuing Jak with the eco teleport power. Jak next encounters them inside containment cells, in which they appear to be comatose (though some of the apes bust out of their cells and attack Jak). There are also several medical monitors along the walls showing X-rays of the apes. Jak also encounters them a few more times in the following rooms. Throughout the rig, ape skeletons may be found lying around covered in cob webs.
While the apes in Far Drop are only in the first stage of their infection, the ones encountered inside the research rig are in their second stage, thus they both have slightly different appearances. While they both have an appearance similar to a gorilla (and in fact appear to be the same exact species), the silverbacks have a purple-white fur with green swirls on their arms, and the franken apes have a more purple appearance with patches of red fur, busted-open incisions with thick staples along them, and thick restraining bolts on their head and arms.
Both variations of the mutant ape are fairly capable alone, though their formidability increases exponentially as they attack in larger groups. They will attack straight on, but will also flank you after circling around. They are quite powerful in their own right, but suffer from their susceptibility to being stunlocked, as each individual hit from a gunstaff mod will stop them in their tracks for a split second. They also each have a unique sort of rage mode, similar to the alpha and hyper mutants.
Franken apes have three melee attacks. First is a rarely used swing of their right arm, which deals average damage. Second is a much more common smash of both their arms, which deals slightly more damage. And finally is a move that is identical to the alpha mutant's grappling strike, the attacking ape will primarily use this when there is some distance between you and them and will run directly towards you with both arms outstretched. However, it does not actually grab you but simply hit you and roll through, dealing severe damage on contact.
Unlike the silverbacks, their rage mode can activate at any point, though it is noticeably slower before it is fully working. During this start-up time the affected ape's hue will grow more and more red over time. Its damage output is unaffected, but it has a slightly higher speed. The only way to cancel a franken ape's rage mode is to hit it with melee attacks.