Atomic

An Atomic is an energy-based creature found in Metroid Prime 3: Corruption and possibly Super Metroid. It is virtually identical to the Pulse Bombu of Metroid Prime and the Harmony Class Drone of Metroid Prime 2: Echoes: at every few seconds, they drop one of their regenerative, explosive segments that compose their bodies and the creatures collide onto Samus if she charges her Beams near them (as they are attracted to the intense concentration), subsequently damaging her with their energized bodies. The two main differences to be seen is the Atomic's coloration (red and white) being vastly different from the others, and that the variation in Metroid Prime is only vulnerable to the electrical Wave Beam. Atomics can only be killed by a Charged shot from any Beam weapon and are found on planet Bryyo and the GFS Valhalla in Corruption.

In Super Metroid, there are unnamed entities found in the Wrecked Ship that are possibly Atomics. While the ship's energy is being drained by the high-ranked Space Pirate called Phantoon, these 'Atomics' are encased in spherical glass casings; once the Pirate is defeated and the ship is operational, all of the Atomics break free from their containment and slowly home in on Samus when she's in close proximity. Although these beings have colorings that make them resemble more like Pulse Bombus (green and yellow), they're considered to be Atomics for the sole reason that they're vulnerable to any Beam weapon's Charged shot as well. However, these entities can also be damaged by all other weapons in Samus's arsenal, including normal Beam shots.

There is an extremely similar but also officially unnamed construct that appears in the Space Pirate Mothership in Metroid: Zero Mission. Bearing similarity to both the Wrecked Ship's Atomics and Pulse Bombus in color only, these constructs are unlike any of the other variations mentioned in the above paragraphs. They attack by accurately shooting bolts of electricity at Samus, but not before giving themselves away by glowing and charging their bodies; their attack is strong enough to break through the powerful Screw Attack. Surprisingly, instead of making any attempt to approach their target, they constantly keep their distance and fly away when Samus gets too close (especially if she's using the Screw Attack). Finally, these unnamed creatures are invulnerable to all Beam weapons, and can only be damaged with Missiles and the Screw Attack (sharing two weaknesses with the Atomics from Super Metroid)

Logbook entry
Metroid Prime 3: Corruption: "Atomics are creatures composed entirely of energy. A strong energy blast is adequate to destabilize the Atomic and cause it to explode. They are sustained by their core, which generates a constant supply of electricity. When an abundance of energy has been produced, the Atomic will discharge a section of its body in the form of an explosive projectile. When near sources of energy of an opposite polarization, the Atomic will respond aggressively."

Trivia

 * The Wrecked Ship's Atomics may have originally been used as power sources. After they escape from the glass casings which contained them, the broken capsules seem to be short-circuiting, indicating they were directly connected to the Atomics.
 * The unnamed creatures from Zero Mission are one of the few beings in the Metroid universe that can simultaneously break through the Screw Attack and instantly damage Samus Aran.


 * These creatures do not appear in the game's Easy Mode.