Nonsentient Allies

 The GURPS Ally (p. B36) advantage expressly allows nonsentient (IQ 0) allies (and even specifies that they have no cap on point cost relative to the PC; p. B37), and GURPS allows (more-or-less) for almost anything to be built as a "character". However, many GURPS GMs seem to find this to be pretty abusable and don't allow or use this option.