Gene Gogolak was the main antagonist of the episode "Arcadia" of the tv series The X-Files.
Gene Gogolak was the mastermind behind the creation of The Falls at Arcadia, a planned community with a strikingly strict set of rules for its residents. Gogolak was a businessman who worked for Pier 9 Imports and often traveled to the Far East to countries such as Tibet and Taiwan. While there, he apparently obtained the ability to summon a tulpa, which took the form as the Ubermenscher.
Gogolak used the Ubermenscher to enforce his will upon the community, occasionally using it to kill resident who failed to conform, including Dave and Nancy Kline. When Rob and Laura Petrie moved in, Gogolak had Win Shroeder discern whatever he could about them. Ultimately, Gogolak had the Ubermenchser attack Mike Raskub for expressing concern over the Petries' safety.
Mulder eventually figured out that Gogolak was behind the mysterious disappearances that occurred in the neighborhood, which prompted Gogolak to sic the Ubermenscher on him. However, Mulder handcuffed Gogolak to a mailbox while the Ubermenscher was on the prowl.
Unable to control the being, Gogolak was attacked and killed by his own monster, which then caused the monster to cease existing.