TEC-XX, simply known as TEC, is a supercomputer designed and built by the X-Naut leader. Sir Grodus, for the purpose of aiding the X-Nauts in their quest for the Crystal Stars. He only appears in Paper Mario: The Thousand-Year Door.
TEC-XX is a large computer. He also appears to have one "eye" where he uses to observe Peach.
After Princess Peach is captured, a bug in his AI causes him to fall in love with her. TEC has Peach carry out all sorts of strange, crazy, and ridiculous missions. The princess ends up dancing with a hologram of herself, disguising herself as an X-Naut, answering a quiz containing vital information, and even stealing info from Grodus after tossing aside her clothes in order for an invisibility effect to work. TEC finally tells that Peach is located in X-Naut Fortress on the Moon and must escape before it is too late. Eventually, Grodus and the X-Nauts find out of TEC's mutiny, and Grodus orders TEC to be shut down. Before all of his memory is completely wiped, Mario stumbles across him. He makes it possible for Mario to escape, before he shuts down for good. However, while Mario is looking through his mail, Goombella revealed that TEC had somehow survived his order and is up and running. Mario can go visit TEC again and TEC promises not to let any X-Nauts back into the Fortress.
- TEC replaces Twink's role from Paper Mario.
- The XX in TEC's name is shorthand for "Double Cross". This is a reference to when TEC eventually double crosses his master, Grodus.
- TEC could be a reference to a similar computerized character HAL from the movie: 2001: A Space Odyssey.