The "Laser Light Cannon" is a powerful magic cannon formerly owned by Rose Quartz. It is the titular object of the first episode it appears in, "Laser Light Cannon", in which it was used to destroy the Red Eye, and "The Return", in which it was used in conjunction with the Quartizine Trio in an unsuccessful attempt to destroy an incoming Gem Warship.
The Laser Light Cannon is a large, pink, cannon-type weapon made up of a crystalline material. It is bulky, extremely heavy, and is implied to be considerably durable. The barrel, backside, and hinges of the cannon all follow a floral motif, which is reflective of the cannon's original owner.
The cannon seems to have a process of activation that resembles the blooming of a rose. The inactive form of the Laser Light cannon has an appearance similar to a developing rose bud. Once the key phrase is stated, the cannon glows as it charges in preparation for firing. In the active form, the muzzle of the cannon appears to bloom like a fully developed rose then fires its volley. The cannon fires intense beams of peachy-pink light which morph in the air to take the vague shape of Rose Quartz. The cannon does not require any sort of ammunition. There is no visible firing mechanism, although it appears to be activated by the phrase "If every pork chop were perfect, we wouldn't have hot dogs." The beam is extremely powerful and is identified as the only thing (on Earth) strong enough to destroy the Red Eye. Additionally, when it is used alongside the Quartizine Trio, three additional laser light cannons, the multiple beams become synchronized and appear to twirl around each other presumably amplifying the strength of combined beam.
The history of the cannon prior to the events of "Laser Light Cannon" is, for the most part, unknown. This includes its creation and its previous usage, though it may have been used by the Crystal Gems during their rebellion against the Gem Homeworld.
When Beach City is threatened by the approaching Red Eye, Garnet tells Steven that Rose's light cannon is the only thing powerful enough to destroy it. However, the Gems had lost track of it in the time since Rose gave up her physical form to give birth to Steven. Steven tracks down the cannon, locating it in his father's storage unit. Steven retrieves the cannon and, with his father's help, returns it to the waiting gems just as the situation becomes increasingly dire, as the gravitational pull from the approaching Red Eye continues to grow stronger. The Gems struggle to activate the cannon, until Steven remembers his father's often repeated aphorism "If every pork chop were perfect, we wouldn't have hot dogs." This quote, when spoken aloud, is what ends up activating the cannon. After a brief period of setup, the cannon fires upon and successfully destroys the Earth-bound Red Eye. Later, in The Return, it was used alongside the Quartizine Trio (a trio of cannon-type weapons which appear to be likewise to the singular Laser Light Cannon) in an attempt to destroy the Gem Warship, but the beams were dispersed harmlessly.
- The back end of the cannon features a design that strongly resembles Steven's shield weapon.
- When Greg says his signature phrase "If every pork chop were perfect, we wouldn't have hot dogs!" outside of the storage unit containing the cannon, the cannon gives off a slight pink glow, foreshadowing how it would later be activated. This glow is also how Steven was originally able to locate it.
- This also happens while the cannon is being driven to the Crystal Gems; Greg repeats the phrase, and the cannon, sitting in the back of the vehicle, glows slightly.
- The floral motif and pink coloration of the cannon could imply that Rose Quartz created, designed and/or built the weapon herself.