A weapon similar in nature to a Railgun, but is much more powerful. It is also called a Grav Gun and is a type of Repulsor Weapon.
A Gravity Gun works similar to a Railgun, using not chemical forces to force ammunition down a barrel. Instead of electrical forces, a Gravity Gun uses, as it's name would suggest, gravity to shoot a projectile at a small percentage of the speed of light, which can cause devastating damage when compared to traditional guns. This is done using gravity generators and manipulators. Gravity Guns are often used with Infinite Mass Missile ammunition for extra devastation.
Like all tech, its appearance is based on who built it and the design. Gravity Guns are typically long barrels of sorts, the insides bearing gravity generators.