Frankenturrets are bizarre Sentry Turret-Weighted Storage Cube hybrids in the single-player campaign of Portal 2. Created by Wheatley in order to complete test chambers when he had no available test subjects, they are first introduced in Chapter 8, The Itch.

Frankenturrets do not speak, and instead emit incomprehensible chirping sounds. They generally serve as Wheatley's replacement for Storage Cubes once Chell is available as his test subject. They are harmless, their the only difference from normal cubes being that Frankenturrets will hop around aimlessly when not placed on a button. When picked up by Chell, they retract their legs inside the cube. If they fall over on their sides or upside down, they will wave their legs, trying to get up.