Zombie researchers are humans that have been infected with an X Parasite that already contains the DNA of a slime creature. However, it is witnessed in-game that the reverse is possible as well: an X Parasite containing human DNA can merge with a slime bioform to create an undead researcher. Their X Parasite infections have caused their bodies to be reduced to large puddles of viscous sludge. These pools of sludge seem to be free of infection by themselves, since when a free-roaming X Parasite merges with one of these, it transforms into a mobile being with a similar body structure to a human. These new creatures slowly lurch through the Space Station corridors, usually on the Main Deck, or throughout the artificial sections of the various sectors. They don't seem to have a great deal of intelligence, given the fact that they only have basic survival behavior; they only seem to swipe their limbs at nearby organisms by habit. One shot from the unmodified Arm Cannon of the Fusion Suit is enough to reduce these organisms back to a puddle of sludge, and expel the X Parasite out. The puddles of sludge, however, cannot be destroyed. Any roaming X Parasite is capable of reanimating the sludge.
"These shambling creatures are probably the result of X parasites absorbing a slime creature's DNA then infesting staff researchers. They're remarkably similar to zombies."
- The name-tag depicted in concept art appears to read "S.C.R. 7".
- Adam Malkovich at one point in the events of Metroid Fusion hypothesized that the collective knowledge of the high-clearance researchers throughout the BSL Station was absorbed by the X Parasites, in order for them to gain more knowledge of the station. One example is the Scientist, which was an X Parasite mimicking a scientist. Using its new-found knowledge, it tried to indirectly set off the explosives for the station's auto destruct sequence. This was an attempt to eliminate Samus Aran, in order to give the X Parasites on SR388 a larger chance of survival. Adam subsequently theorized that the researchers on board the station would be of no further use, so therefore would only be useful as sustenance. These "Zombie researchers" may only be what is left after the X Parasites had finished consuming the humans on board.
- It would seem the X are capable of taking the shape of inorganic materials, as each Zombie researcher appears to wear an identical tattered lab coat that is nowhere to be found in the creature's sludge-pool form (suggesting it may have originated from the X Parasite's initial human host). Based on Samus' battle with the SA-X, the X seemingly use organic material to mold it into the shape of artificial segments that the species cannot directly infect/copy.
- In early builds of Metroid Fusion, the researchers were much more Frankenstein-like, and green in color. They were also seen in a room not accessible in the final game, but reachable by hacking.