Rain D.'s Red variant with fewer knockbacks, can knockback cat units and has a small boost in attack power and health. However, it both attacks and moves slower than its original counterpart.
The only difference between fighting this enemy and Rain D. is its ability to knock back your cats and its classification as a Red enemy. Using any Fish Cat variant (Crazed Fish Cat, Li'l Island Cat, etc.) will be able to kill this enemy quite quickly.