Music graduate George Garratt, 19, changed his name by deed poll online for £10, reports the Daily Telegraph.
Captain Fantastic said: "I wanted to be unique. I decided upon a theme of superheroes."
He joins a number of people with unusually long names, including Rhoshandiatellyneshiaunneveshenk Koyaanisquatsiuth Williams, a girl born in Texas in 1984.
The teenager, from Glastonbury, added that while he thought the new name was "crazy", his grandmother was no longer speaking to him. (Daily Telegraph)