Sonic Underground (1999)

S1E23 Hedgehog in the Iron Mask

On their latest adventure to locate their mother, the Hedgehogs arrive at a prison tower, where they meet a masked figure claiming to be part of their family. However, this individual is merely a pawn in Robotnik's ongoing scheme to ensnare them. His presence sows discord among the siblings, leading to the disbandment of the Underground. As a result, they find themselves exposed and ultimately cornered.