The Mur'row Parasites

The Crew of the Paragon, an interdimensional exploratory team, found one nearby parallel world, previously explored by an earlier shuttle which never returned.
That complement of crew also searched the strange world of unstable ground and tree leaves with all the colors of autumn until they fall off and turn vibrant green as they decompose.
One lone crewmember took a sting on the back of the head from a small parasite with a disk-like body and a short tail capable of connecting into the central nervous system of homo sapiens and other mammals. When so connected, the two organisms underwent a struggle of wills between the two brains controlling the two connected bodies. The parasite would have little chance of winning if not for a sedating chemical it excreted.
The crew was slowly overcome, not so much by the parasites, but by the hostile action of just two hosts controlled by the parasites luring the free-willed ones into catacombs of a long dead civilization with a strong dislike of tomb robbers, so much so that the catacombs were riddled with death traps.
Finally, the last survivors were the Captain and First Mate, both under the control of the parasites, which called themselves the Mur'row. In an attempt to use the visitors' ship to bring the remainder of the specie to the home world of these suitable hosts, one of the two initiated repairs and oversaw the slow process of refueling (after the battle between the two specie had resulted in sabotage scuttling the ship). The other used the onboard stasis chamber to "freeze" itself and its host's bodies in an unconscious state with microorganisms performing the tasks of removing dead cells and cloning stem cells to replace them in a dreamless hibernation slumber, keeping them ageless for potentially a thousand years, so that one of the two would be in prime condition to insinuate itself into the homo sapiens whenever the ship was made operational.
The other host body aged badly under the direction of the parasite, but the hideous disfigurement caused by the incompatibilities between the two species would not be a problem as long as the "frozen" one remained in pristine shape and able to lure more homo sapiens into contact with the preserved seeds of their parasitic race.
As the years passed and the repairs progressed, it appeared their plan was foolproof.
But then a new kind of fools entered the scene.
The crew of the Paragon knew of the lost expedition, but could not have dreamed that they would land nearly on top of it. Many different things can go wrong with an expedition to a parallel world. There was no reason to believe a hostile specie was the reason this time. They might as well go about exploring the planet and those intriguing catacombs below it.