Whether the gopher was real or not, Carl would still blow up the golf course, the judge would be out $80,000, and everybody would still get laid. It’s not about whether or not the gopher exists after the initial complaint, but more that Carl believes it exists and that he’s motivated to go to the most extreme measures to ensure it is killed. So really, Caddyshack fans can believe whatever they want in regards to this theory, unless of course Bill Murray or someone confirms the gopher was legit.
Article source: https://www.cinemablend.com/news/2493748/was-the-gopher-from-caddyshack-all-in-the-groundskeepers-head