Harold Allen Ramis was an American actor, director, and writer specializing in comedy. His best-known film acting roles are as Egon Spengler in Ghostbusters and Russell Ziskey in Stripes ; he also co-wrote both films. As a writer-director, his films include the comedies Caddyshack , National Lampoon's Vacation , Groundhog Day and Analyze This . Ramis was the original head writer of the television series SCTV, on which he also performed, and one of three screenwriters of the film National Lampoon's Animal House .