Phaser
Phasers are the primary energy weapon used in Star Trek. They can scale from concealable hand weapons to starship weapons.
Nature
Phasers are particle beams that usually heat materials they strike. They often start chain reactions of an unknown nature that continue well after the beam stops striking the target. Phasers at full power have been known to make their targets completely disappear, an effect often described as "vaporization", although it is never accompanied by the violent explosion and superheated cloud of vapor one would expect from vaporizing a target such as a human in about a second.