“Star Trek: Discovery” will see a most unwelcome guest come aboard in this week’s episode.

Harry Mudd (Rainn Wilson), the intergalactic huckster who was re-introduced into the franchise’s universe last week, sneaks aboard the Discovery in an effort to learn the secrets of the ship’s spore drive. Somehow, Mudd is able to keep the ship trapped in a 30 minute time loop, meaning he can destroy the ship over and over again, repeating the process until he is able to learn how the drive works.

In an exclusive clip of the episode, Burnham (Sonequa Martin-Green) and Lt. Tyler (Shazad Latif) find Mudd sitting in engineering at the controls of the drive. He asks them to save time and simply tell him how the drive functions. Tyler fires, but Mudd has put up force fields to protect himself. The computer lets Burnham and Tyler know that the drive is approaching an overload and will soon destroy the ship. Burnham says that he is mad, to which he replies, “No, I’m Mudd.”

“Star Trek: Discovery” episode 7, titled “Magic to Make the Sanest Man Go Mad,” will be available to stream beginning at 8:30 p.m. ET on CBS All Access.