Wave Beam

The Wave Beam is a beam that Samus gets in all of her games, save for Metroid Prime 2: Echoes and Metroid Prime 3: Corruption (though she gains the Annihilator Beam and Grapple Voltage, which have a few similar properties). It fires electrical energy (often in the shape of a sine curve) that can usually go through walls.

In Metroid: Zero Mission, Super Metroid, and Metroid Fusion the Wave Beam was a beam of electrical energy that could go through walls. In these games, it acted as a power-up to the normal beam(s) that Samus had acquired thus far. In Super Metroid, it could be added to any other combination of beams to make them go through walls. In Metroid Fusion, it adds a "go through walls" effect to the already-acquired Charge, Wide, and Plasma Beams. In Zero Mission, it added a widening effect and a phase effect to whatever beams Samus has by that point (Samus could actually obtain the item without any other beams, but she could have the ice, charge, long, and even plasma effects by then, due to the game's non-linear nature).

In Metroid and Metroid II: Return of Samus, the wave beam generated a single bolt that moved forward in a sine curve and passed through walls. Unlike the other three side-scrollers, the wave beam in these games was possessed instead of the others, rather than with the others - for example, in the original Metroid, Samus could not normally have both the Wave Beam and Ice Beam equipped at the same time.

In Metroid Prime, the Wave Beam takes on a different role. Here, it is one of the three "elemental" beams, it representing the element of Electricity. It cannot be combined with the other beams. The Wave Beam does not go through walls, but, if the player is locked on to an enemy, the beam has a homing feature that can follow an enemy around until it hits. The Wave Beam is acquired after defeating a Sheegoth in the Chapel of the Elders (located in Phendrana Drifts). The Wave Beam can damage the purple form of the Metroid Prime, as its color scheme is purple. When fired normally, it launches three separate rounds that undulate inwards and outwards continuously with impressive homing. When charged, it fires a slower-moving single round that, when used on a few certain enemies, can cause a stunning effect. It's uses outside of battle include powering conduits and opening purple doors. It is the only weapon that can destroy the Pulse Bombou and the Scatter Bombu.

Also in Metroid Prime, the Wave Beam can also be upgraded with a Charge Combo called the Wavebuster. This allows Samus to fire a perpetual wave of electrical energy at an enemy. It has a limited homing feature (It will automatically attack a nearby enemy if it is within the range that the Wavebuster can attack from.)This attack uses up 10 missiles to activate and 5 missiles per second afterward. Although it has an extreme ammunition cost with less damage-per-missile than the Super Missile, it deals damage at an incredible rate, making it valuable at quickly defeating enemies in a pinch.