Scorpius is the boss of Toxic Caves in the game Sonic Spinball. Scorpius is a robot scorpion, but has Robotnik's face. Sonic battles him after collecting three Chaos Emeralds in the Toxic Caves, the first (and lowest) level in the Veg-O-Fortress.
Scorpius can use its extensible tail as a shield, and Sonic must jump beneath the tail in order to attack Scorpius' body. After a certain number of hits, the tail will detach and Sonic can attack Scorpius' body directly.
Scorpius also appeared in issue #6 of the Archie Comics series Sonic the Hedgehog. Its role was the same as in Sonic Spinball, and it was dispatched by the Freedom Fighter along with its ally, Rexxon.