Charge Beam

The Charge Beam is a more potent version of Samus Aran's normal beam. It first appeared in Super Metroid and has been in all games since.

Description
After acquiring the Charge Beam, Samus can focus energy into her Arm Cannon, and it can be released at any time. This process can be seen in the Metroid: Other M trailer. The resulting charged energy, when releasing the stored energy, is many times more powerful than firing a normal beam (though the exact power varies between games), and in certain enemies can only be damaged by a charged version of the beam. Its appearance is reminiscent of the beam(s) currently in use, and usually takes the form of a concentrated ball of energy. Super Metroid has two hidden Charge Beam features. The first is that, when holding the charge and going into a Morph Ball, Samus will release five bombs, four of them bouncing away. The second, when holding down the charge and equipping only one other beam while highlighting the Power Bomb, Samus can let loose a special beam attack at the cost of Power Bombs.

Jump combo
Seen in Super Metroid, Metroid Fusion, and Zero Mission, Samus has the ability to perform a damaging spin-attack when the Charge Beam is fully charged. By somersaulting into the enemy, it will be hurt by damage roughly equal to the charged current beam. This attack can offer safety while getting rid of enemies at the same time. However it cannot destroy every enemy, and if their health is high enough to survive the attack, Samus will take damage as well. Of course, this ability becomes obsolete when Samus acquires the Screw Attack.

An interesting note is that in Metroid Fusion the normal shot along with the charged shot is actually made up of two smaller shots which form its crescent shape.

Prime Series
A factor in the Prime series are the well-hidden Charge Combo abilities, found as separate items. These special add-ons to the particular beams add many special effects and can be highly damaging.

In Metroid Prime 2: Echoes the Dark Beam, Light Beam, and Annihilator Beam have different effects compared to their normal shot. The charged shot of the Dark Beam creates a compact blob of dark matter that, on contact of an enemy, entangles it with dark energy, preventing movement and making it vulnerable to a Missile, not unlike the Ice Beam. The charged Light Beam fires a volley of fast, mildly-homing spherical projectiles; when used close range it can be highly damaging, similar to a shotgun. Charging the Annihilator Beam doesn't do anything special; the attack is not too different from the charged Power Beam, having no homing specialty, but it is more powerful and has a higher damage radius.

The Prime variants of the Charge Beam also have a tractor beam effect on power-ups: as long as Samus holds the charge, it drags the power-ups to her, allowing her to collect them from hard-to-reach areas. The Charge Beam also has the capability of gathering Phazon particles to fire a Phazon-concentrated shot.