Adventures of Sonic the Hedgehog

The Badniks go back to the Mesozoic Era and steal the Emerald of Life, but not before Robotnik kills his Dumbniks to do so by throwing them into the volcano. Sonic is too late to stop him. Robotnik and his morons (who have somehow been resurrected despite getting thrown into the lava) go back to the last three episodes to get the other Emeralds.