Test dummies are robots in Ratchet & Clank, the 2016 re-imagined game, Going Commando, and Up Your Arsenal. They are used by Gadgetron Corporation and Megacorp to test new products, including weapons. Many are fought as enemies, using Gadgetron weapons including the Bomb Glove, Pyrocitor, and the Walloper.
Ratchet & Clank
In the original release, the test dummies were fought as enemies in the Gadgetron site, Kalebo III, during "Get past the blarg". Ratchet and Clank were locked in three Weapons Testing Labs unable to escape until all were destroyed, and a fourth testing lab outside Wendell Lumos' office. Later, the test dummies were racers competing in hoverboard racing events. After Ratchet won against the test dummies, Wendell Lumos gave him the Hologuise, and made him a sponsor for Gadgetron's hoverboards.
In Qwark's version of events, test dummies were initially fought by Ratchet on Veldin during the Galactic Ranger tryouts in "Head to the fairgrounds". Ratchet had to get past them to proceed further. The test dummies were later fought in the Gadgetron Headquarters on Kalebo III, hijacked by the blarg to attack Ratchet. They were fought in two Weapons Testing Labs, though the third lab did not produce any test dummies and instead only produced harmless sheep. Finally, they were fought in the test lab outside Lumos' office.
Up Your Arsenal
In most releases, test dummies are small, metal robots, with yellow and black eyes, and red highlights. They have a sphere used for movement in place of legs. Test dummies appear unintelligent, incapable of speech, and sometimes targeting nothing at all.
In the re-imagined release, test dummies are instead completely yellow robots, with a single green eye, and a Gadgetron logo on their chest. Their right hand contains a flamethrower weapon, in place of them carrying their own weapon. They otherwise retain the humanoid appearance with a sphere for movement.
Test dummies only sometimes target Ratchet, and at other times target nothing at all (or even accidentally hitting each other). They have little armor, and do not pose a threat on their own, and the only threat comes from their numbers or the unpredictable nature of their attacks. Most weapons are useful against them. In the original Ratchet & Clank, the Tesla Claw and Pyrocitor are particularly effective. In the re-imagined release, the Groovitron may be required when they overwhelm Ratchet, but otherwise, the Proton Drum is most effective. In Up Your Arsenal, the Shock Cannon is best suited against them due to their numbers.