Steve Carlsberg is a character in Welcome to Night Vale, and appeared in The Great Thrilling Adventure Hour / Welcome to Night Vale Crossover. He is played by Hal Lublin.
Steve Carlsberg is the brother in law of Cecil Palmer, the main character of Welcome to Night Vale. In the crossover, Steve finds an old, charred book that survived a library cleansing, which claims that the moon is totally real, you'd better believe it, and is actually hundreds of thousands of miles away, and not a shared hallucination sixty feet in the air as most citizens of Night Vale believe.
Steve goes to Mars with Croach the Tracker, Cecil, and a projection of Carlos the Scientist to help figure out why the robots Samuel Bolt and Claxon set up a civic committee in Night Vale to destroy the moon and why that is causing the moon to disappear in Croach's present-day Mars.
Steve is horribly un-helpful in the future. He and Felton nearly get into a fight, and Felton, Croach and Sparks Nevada all express their dislike for Steve. He also didn't bring his temporal shifter with him, which would have been useful to help save the universe. In the end, Steve confesses he thinks of Cecil as his best friend, and laments that none of the citizens of Night Vale will have ever met the citizens of Mars should Dolores County successfully undo everything that happened that day.