Gropius Lysenko was a brilliant biochemist. Weyland-Yutani hired him away from Neo-Pharm when he became known for his experiments with consciousness-altering substances. Lysenko was also in cahoots with Weyland-Yutani who had been using their own Red Giant Line passenger ships for years as cover for their secret and highly illegal experiments on the alien species, Lignuafoeda Acheronsis, commonly known as Xenomorps.
Lysenko was Weyland-Yutani's main researcher aboard the Lunar Maru. Among other things, Lysenko was researching the psychoactive properties of certain Royal Jelly derivatives. He was genetically altering Lignuafoeda Royal Jelly in an attempt to open their alien consciousness to a human scale of understanding while the effect on his own consciousness was unforeseen when he began sampling his own wares and experimenting on himself. Unpredictably, his experiments revealed that the altered jelly greatly accelerated Xenomorphs' productive cycle while the psychic enhancements had negative results with the larva, driving them to insanity.
Lysenko's intake of a royal jelly variant caused him to separate his consciousness-- his mind-- from his physical form, allowing him to throw his mind into the bodies of others. This is how Lysenko communicated with the Trispast Salvage crew of the St. Claire, who were recently acquired and sent by Weyland-Yutani to investigate and recover the remains from, and were subsequently marooned aboard, the Lunar Maru.