Puppet Gun

A sufficiently large gun (larger BFG to Wave Motion Gun) robs its user of being able to look cool by actually wielding it. Solution: Provide a device for aiming and firing the thing by remote control that actually looks like a human-scale gun itself.

Truth in Television: laser designator systems for aerial bombs and missiles often fit this. The laser emitter is carried by a person or mounted on a vehicle and is used to guide the actual missile (which is usually launched from a ship or plane) to its target. Related to Helmet Mounted Sight and Laser Sight. Both are real life uses of a similar principle. See which is not quite so "gun-like" as some fictional depictions.

Not to be confused with a gun that fires puppets.

Anime & Manga

 * Gundam00: Lockon Stratos uses a device that looks like a blocky sort of gun (Our Weapons Will Be Boxy in The Future) to aim and fire the GN Sniper Rifle.
 * Space Battleship Yamato: While the original Wave Motion Gun wasn't really like this, the Wave Motion Gun type weapons used by Leader Desler certainly were.
 * Scryed: One of the villains had an Alter in the shape of a huge, floating gun, which he aimed and fired using a more normal-sized Hand Cannon.
 * To fire the big gun the titular Girl Who Leapt Through Space has to aim a smaller gun.
 * Heroic Age:
 * Not quite the same thing, but in Space Pirate Mito, an entire spaceship can be used as a lightsaber by handling a model-sized version of said spaceship.
 * Sword-based variant in Bleach. Captain Sajin Komamura's Bankai summons a colossal samurai golem, wielding an appropriately sized sword. The giant matches Komamura's movements, so a single swipe on Komamura's scale translates into a crushing blow from the giant that can easily demolish buildings. His Shikai state does something similar, but with only one body part at a time.
 * Mahou Sensei Negima's Chachamaru's Artifact is a cute little Hello-Kitty-looking handheld thingie that designates a target for a gigantic, also cat-themed Kill Sat.

Film

 * In Clear and Present Danger, commandoes on the ground frame a Colombian drug lord for a terrorist attack by targeting his pickup so the bomb falls into it before exploding. Taken from the book of the same name, where John Clark personally lases the pickup truck.

Live Action TV

 * The more advanced mecha Finishing Moves in Engine Sentai Go-onger are aimed with Handle Blasters (steering wheels transformed into guns!)
 * In Power Rangers Time Force, the Quantum Ranger made the dinosaur form of his Humongous Mecha fire its lasers by standing on its back and firing his handgun.
 * Similarly, Kamen Rider Den-O's Gun Form performs the Finishing Move for its Cool Train by pointing his own gun at the enemy and pulling the trigger. While riding atop its "head".

Video Games

 * The Hammer of Dawn from Gears of War falls into this category. It's a Kill Sat that's controlled by a more pistol-like object.
 * The Satellite Laser from Shadow the Hedgehog is similar.
 * In Gunbound, the A-Sate shoots small tracer- lasers that mark the spot where it's minuature Kill Sats are going to fire. Other vehicles can do similar things with lighting and Thor, the resident Kill Sat, which all the other vehicles can ocassionally use but only one is specialized in it.
 * By the same token, the Harbinger/Supernova designator of Ratchet Deadlocked.
 * In Starcraft, Ghosts send laser-guided nuclear strikes.
 * Armed Assault II averts Did Not Do the Research on the subject.
 * While it's not entirely gun-like, Team Fortress 2 has the Engineer's Wrangler. It is basically an Atari joystick duct-taped to a gun, and lets you aim your Sentry at wherever you are looking.
 * The Apollo Lens in  ~Golden Sun: Dark Dawn~ , which must be aimed using a giant statue that amplifies your Psyenergy. A miniaturized version of the controls is located inside said statue.
 * Halo Reach features a fairly realistic laser designator for artillery strikes in some missions.
 * Euclid's C-Finder in Fallout New Vegas looks like a cartoony ray-gun, but it's linked to a solar-powered Kill Sat called ARCHIMEDES II. It's in the possession of a young child when the game starts.
 * Resdient Evil 5 gives the player a pointlessly huge laser designator to use against it's largest boss. It's about the size of a rocket launcher. Chris then re-uses it in Marvel vs. Capcom 3 as one of his Hyper Combos.

Webcomics

 * In MS Paint Adventures: Problem Sleuth, Pickle Inspector aims the Clock Tower Cannon via the Sniper Rifle.