Gunzoo as it appears in Metroid II.
Gunzoos are mechanical defense mechanisms in Metroid II: Return of Samus that attack any intruder near it. Gunzoos are equipped with two automatic weapons aimed forward, and have the ability to levitate. When they fire, a backward piece of armor blows back, very similarly to a modern automatic weapon ejecting ammunition shells. They fire incendiary shells that deal a moderate amount of damage, which cause small explosions on environment surfaces. These robots do take a lot to destroy with normal beam weapons, but the Plasma Beam makes short work of them.
Manual
"This multi-gunned robot fires at anything that moves."