Voir Adventures of Sonic the Hedgehog, Season 1, Vol. 1 - Episode 2

Sonic and Tails find an underground world of diamonds, but they are held captive there by a miserly Mole-Troll. When Robotnik comes to capture them, he accidently frees them from the Mole-Troll, who teams up with Sonic and Tails to defend his riches.