Gravik-nez was an ancient art of hand-to-hand combat originating on the planet Affa. It mostly consisted of direct hand and arm strikes associated with solid stances. When striking, the practitioner would shout or make some other verbal utterance to frighten their opponent and focus their attack. C-3PO was equipped with a faulty subroutine for this martial art. As a result, his attempts to employ gravik-nez, such as when he was body-checked by the Gamorrean guard Thok on board the sail barge of Jabba the Hutt, were less than successful.
In Star Wars: Droids: The Adventures of R2-D2 and C-3PO, C-3PO's demonstration of his martial skill was played up for comedy.