You have to SAAAAAAAAAVE THE WORLD
Omochao's first appearance in SMG4's bloopers is in Sonic the derphog: Eggventure (GET IT!?), where he wakes up Sonic in the beginning and tells him he has to save the world, but not before getting shot by Sonic. He later appears at the very end, telling Sonic he saved the world, before Dr. Robotnik the Teletubby appears and says "The End".
He reappears in Sonic the Derphog: The Item Brick where Sonic found Omochao where Omochao was told the world is saved and throw him out onto the item block.