Writer Chris Brancato was working with MGM on "The Outer Limits", and knew the studio was interested in making a follow-up to "Species". He pitched an idea to executive Greg Foster where this time two hybrid alien women would strike. Foster liked it, but once Brancato went to "Species" producer Frank Mancuso Jr., he asked to "approach this from a different angle, so that we don't have a tired retread of the original, as sequels often are". So Brancato took inspiration from "The Manchurian Candidate", where "somebody on a mission comes back, apparently a hero, but actually with some terrible demon inside", and as "the notion of a grand, unexplored place was the planet Mars", he made the first astronaut on Mars – as according to NASA scientists consulted by Brancato, human exploration of Mars was "a possibility – just a very expensive one" – be infected by alien DNA. Mancuso approved the idea, and thus Brancato explored how this new villain was one "for whom we can briefly feel a strange, Wolf Man-like sympathy – he's not responsible for having been turned into a monster" and had him face an alien woman similar to Sil, raising the doubt on whether they would battle or mate. As Natasha Henstridge was unconfirmed to return, Brancato wrote the new female, Eve, as if it was "either Natasha or a similarly beautiful woman". Henstridge still liked the script enough and the idea of working with director Peter Medak to sign for the sequel. Brancato decided to bring back two of the surviving characters from "Species", Michael Madsen's Press Lennox and Marg Helgenberger's Dr. Laura Baker feeling they "were essential to bring the audience back in", but knowing Forest Whitaker was probably too busy to return as Dan Smithson, he wrote a similar African American character in the one eventually portrayed by Mykelti Williamson. Mancuso had another script done simultaneously to Brancato's, which reportedly explored the cliffhanger at end of "Species" where a rat was infected after eating Sil's remains. Mancuso brought in to direct Peter Medak, responsible for the 1980 horror film "The Changeling".