Ghost Pendulum is the second boss of Sonic Rush Adventure, appearing at the end of Machine Labyrinth, the game's second level. Presumably a creation of Eggman Nega, this robotic crane-thing is encountered after Sonic and Tails track down the lost Marine. Although the raccoon demands to fight it herself, Sonic leaves Tails to watch her, and goes to wreck up this bizarre stationary opponent.
Like all Rush Adventure bosses, the Ghost Pendulum's fight arena is 3D in contrast to the 2D platforming of the game's regular stages. The robot hangs far, far above the player's ring-shaped platform, its red control gem miles out of range of a spin attack. The boss must be beaten by jumping at the spherical pendulums it rotates above Sonic's head; whack one of the powerfully enough, and it will arc upwards to smash the boss in the face. As the fight proceeds, the robot adds two additional, heavier pendulums, and they start to extrude spikes on occasion. Also, the machine starts dropping a plate from its underside, sending out shockwaves which have to be avoided.
The heavier red and yellow spheres can take several bashes to connect with the robot's head, but they compensate for this by doing more damage. Eventually, the robot collapses out of the air, and the player can deliver the coup de grâce with a final strike to the red gem.