Appa's armor was a set of protective plates worn by Appa during the invasion of the Fire Nation as a shield from the various defenses that the Fire Nation domestic forces employed, including fireballs, spears, and other projectiles. Invented, drafted, and constructed by Sokka, the armor was durable and custom-made for a flying bison to use in combat. The armor had the drawback of being cumbersome, however, causing Appa to tire quickly.