Space Pirates are a sentient species from the Metroid series. They are usually one of the main enemies of Samus Aran and the Galactic Federation, and are often blown up in large numbers by them because of it. In many of the Metroid games, their mission is to cultivate the energy sapping power of the Metroids for their own use, and in the Prime games, the very mutagenic, semi-sentient substance known as Phazon, to take control of the universe. Although pirates they come in many different shapes and sizes (due to experiments on themselves), they almost always feature bug and lobster-like features.
Kraid, Ridley and Mother Brain are all considered rulers of the Space Pirates. There is also Weavel, a Bounty Hunter/former Pirate general (like Samus) who is frequently hired by the Pirates. His injuries from a fight with Samus required a experiment where his brain and spinal cord was placed in a suit that acts as a life support system. He appears in Metroid Prime: Hunters as a playable character in multiplayer, and as a boss.
A typical Pirate Trooper in Metroid Prime 2: Echoes.