The Glastonbury, England, teenager -- originally named George Garratt -- said his new name, which is thought to be the world's longest, has so outraged his grandmother that she is no longer speaking to him, The Telegraph reported Monday.
The teen said he used an online service to officially change his name for a $20 fee.
"I wanted to be unique," Captain Fantastic said of his name choice. "I decided upon a theme of superheroes."
Celebrity Breakups and divorces of 2014 [PHOTOS]