Earthworm Jim 3D is a platform game, the third in the Earthworm Jim series. It is a sequel to Earthworm Jim and Earthworm Jim 2, and the first game in the series to not be developed by Shiny Entertainment, which had recently instituted a strict "no sequels" policy. Interplay Entertainment, having recently purchased the Earthworm Jim rights, handed the franchise off to VIS Interactive. The game suffered a difficult, prolonged development cycle and was repeatedly delayed until it was released in 1999 for the Nintendo 64 and Microsoft Windows. The game was not received well, with critics claiming that the charm of the originals was lost, and that despite the long development period, the game still felt sloppy and lacked previously promoted features.

Earthworm Jim is hit by a flying cow that sends him into a coma. Jim awakens within his own subconscious and discovers he has gone insane. His past villains have entered his subconscious and if something doesn't happen soon, Jim will be in the coma forever. His super ego has been unleashed within his subconscious to stop the madness. To restore his sanity he must find the Golden Udders of lucidity. When Jim enters his subconscious, he finds out that his four mind chambers have been taken over by his worst fears. He must collect Golden Udders to unlock the other three chambers and Green Marbles to unlock the levels within the chamber. Jim defeats four villains who took over his mind chambers, and finally faces the personification of his trauma: Earthworm Kim.