From Sonic Retro
Shield Hunter, シールドハンター, is a GUN robot that appears in some of the stages of Sonic Adventure 2 and part of the Hunter series. Its either a Gun Hunter or a Laser Hunter, both with a large physical red with the number 02 emblazed on them. When the Hunter is using it, the only way to destroy it is to either summersalt its legs or hit it from behind. When the Hunter is not using the shield, it will use its laser cannon and it can be then destroyed as any normal Hunter. There's a second model, carrying the same red shield but with the 01 emblazed instead, appearing exclusively in Crazy Gadget. There's yet another model, carrying a black shield instead (and being 02), and they appear exclusively in Security Hall. Neither of the latter seem to have different behaviours from the default one. Every model award 200 points when destroyed.