Toxic Pools boss is the first boss that appears in the 8-bit version of Sonic the Hedgehog Spinball. It appears in a separated pinball arena in the Toxic Pools. It replaces Scorpius from the 16-bit version of Sonic the Hedgehog Spinball with a dark hovering robot resembling Robotnik's head.
When the player enters the pinball area where the boss battle takes place, the Toxic Pool boss appears above the center of the pinball arena, where it floats around and spits out one or more sparkling red projectiles at the lower part of the arena. However, it never comes down and instead stays in the higher sections of the arena. The sparkling projectiles do not hurt the player, but instead explode upon contact with Sonic and bounce him backwards.
The pinball arena is separated from the rest of the regular level, and there are only a few obstacles here that can restrict the player's progress. Cluckbirds fly around the center part of the pinball arena where they block the nearest Sewer Warp which can take the player to the highest point of the pinball arena. While this pinball arena only features two transport pipes at the sides, the center drain below the flippers and the slingshots can send the player back to the regular Toxic Pools level, meaning the player has to come back to the arena with the Toxic Pools boss the same way he/she got there the first time.
To reach the higher sections of the Pinball arena, the player has to use the flippers. To defeat the Toxic Pool Boss, the player has to hit it six times. When defeated, it will explode and fall down from the pinball arena. Each hit on the Toxic Pool Boss grants the player 1,000 points, and destroying it gives 500,000 points.