 He then gives the two the assignment of gathering Crystals that lay scattered throughout time and keep them from the hands of Uka Uka and Doctor Cortex.During Crash's final fight against Doctor Neo Cortex, Aku Aku fends off Uka Uka's attacks while the fight is in session.Aku Aku appears in "Crash Team Racing" as a tutor for Crash, Coco, Polar and Pura, giving them useful tips and tricks throughout the game.