Sonic Adventure 2 is the first mainstream Sonic game to incorporate other robotic enemies besides badniks and the second to use ghosts as a threat.
Eggman’s robots, as usual, drop a small animal when destroyed. Like in Sonic Adventure they can be collected and taken to the Chao Garden.
GUN robots are powered up by Chaos Drives instead of small animals. They drop one (the colour is always random) when they're destroyed.
- Beetle series: Mono Beetle, Gun Beetle, Bomb Beetle, Gun Wing, Bomb Wing, Spark Beetle, Spring Beetle, Gold Beetle
- Hunter series: Gun Hunter, Laser Hunter, Shield Hunter
- Rhino series: Rhino Jet, Rhino Cannon, Rhino Spike, Rhino Metal
- Hawk series: Gun Hawk, Laser Hawk, Gum Hawk, Sky Hawk
- Hornet series: Hornet-3, Hornet-6, Hornet-9, Laser Hornet, Phoenix
- Fighter series: Blue Eagle
- Artificial Chaos series: Artificial Chaos P-1, (Artificial Chaos) Guard Type, (Artificial Chaos) Float Type, Artificial Chaos P-100
- Boo (normal and attack type), Boom Boo