Omega Weapon's exact appearance varies, but it is most often a quadrupedal gray and silver entity with blue and yellow details. It is biomechanical, sometimes with gears or other robotic features on its body. In games where they appear alongside each other, Omega Weapon is almost always a palette swap of Ultima Weapon. Often, the player must first defeat Ultima Weapon to challenge Omega Weapon, and the two sometimes fight similarly. Omega Weapon's origins vary, if it has any origin given at all.