The assault phaser was a much stronger version of the phasers commonly used as ship mounted weapons on Federation starships. It was developed simultaneously by the Federation and the Klingon Empire, with the same basic premise driving both designs. Due to the energy required to power the weapon, ships equipped with assault phasers occasionally found their systems overloaded after using them, leaving them vulnerable to attack. The Federation Yamato-class prototype was the only starship known to possess two assault phaser emitters, while starbases employed them as a primary defensive weapon. (TOS video game: Klingon Academy)