Power Trooper

Power Troopers are special types of Space Pirates that were modified so they could use Samus Aran's Power Beam. This made them incredibly strong, and invulnerable to all weapons except the Power Beam itself. Thus, they have a weakness to it as well as the Super Missile, the Power Charge Combo.

Power Troopers appeared in Metroid Prime and are found in the Phazon Mines as a relatively common enemy.