Samus's beams

Samus Aran's Power Suit has several interchangeable, upgradeable components. One of those is her beam weapon. Various forms of power beams and missiles, some requiring ammunition, are useful for taking advantage of an enemy's vulnerabilities. In some Metroid games beam upgrades would replace one another and always become more powerful. In others, beams are interchangeable and each has unique advantages.

Note, that some beams and screenshots of beams contain unavoidable spoilers.

Samus's Beams
Samus's beam weapons (with the exception of the Dark, Light, Annihilator and to some extent the Phazon Beam) have unlimited ammo. In early Metroid games she had to change between them by setting one down at a Chozo Statue and picking another one up. In the Metroid Prime games, Samus can change beams at any time. In Metroid Fusion her new beams simply 'fused' together into one single beam. The icons for beams in Metroid Prime imply that Samus changes beams by moving the hand inside her gun-arm to a specific handshapes. In the Metroid Prime games, changing beams also changed what her cannon looked like.

Samus's Beam Upgrades
Sometimes Samus can get upgrades that affect all her beams.

Special Combo Abilities
These abilities combine Samus's weapons for unique effects.

Trivia

 * The beam's name, "Hyper Beam" is also the name of an attack from Pokémon.