Crystal is the love interest of Shaggy Rogers from Scooby-Doo And The Alien Invaders.
Shaggy first met her and thinks that she's beautiful. She meets Fred, Daphne and Velma at the cafe. Shaggy begins a relationship with her and daydreams about her.
She, Amber, Scooby and Shaggy investigated the cave in the canyon and discover that the gang has been kidnapped by the aliens. However, Crystal and Amber reveal themselves to be real aliens from a planet 20 light years away.
They can only use information about Earth from television broadcasts from the 60s.
She and Amber helped Shaggy, Scooby and the gang to stop the SALF crew and tied them up to allow the SALF crew including Steve, Laura and Max to be arrested.
In the end, she and Amber bid Shaggy and Scooby farewell as they return to their home planet as Shaggy and Scooby become saddened, but Velma tries to cheer them up with Scooby Snacks.