Screenwriter/Director Chris Columbus sold his first movie script for Jocks while still a film student at New York University; although heavily rewritten by others for the screen, this piece got Columbus' foot in the big-time door. His breakthrough script for producer Steven Spielberg was for Gremlins, and was allegedly inspired by its writer's dreams of mice at his fingers. The film, which blended warmth and whimsy with violent slapstick and some truly mean-spirited moments, was even more vicious than what was seen onscreen before it was cleaned up by Spielberg, himself. The success of Gremlins secured Columbus future writing assignments on such Spielberg projects as Young Sherlock Holmes and The Goonies (both 1985). He also developed the concept for a 1986 television cartoon series, Galaxy High School, about an extraterrestrial school populated by weird-looking space aliens. Columbus was eventually given a chance to direct the medium-budget teen comedy Adventures in Babysitting in 1988. He followed this with Home Alone (1990), directed from a script by John Hughes, which made incredible amounts of money and planted Columbus firmly on the Hollywood "A" list. Columbus continued to alternate between writing and directing as a Hollywood fixture in the '90s, churning out such box-office bonanzas as Home Alone 2: Lost in New York (1992) and Mrs. Doubtfire (1993), among other titles, before directing two even bigger blockbusters: Harry Potter and the Sorcerer's Stone (2001) and its sequel the following year, Harry Potter and the Chamber of Secrets.