Crast, alternatively known as food-kin, constituted a crustacean species originating from Pria. They shared a symbiotic bond with the Priapulins. The incubation of Crast eggs commenced following their digestion by a Priapulin. The Crast willingly served as sustenance for the Priapulins, and in exchange, the Priapulins provided care for the Crast offspring.
Priapulins needed to eat Crast before their offspring began to spoil.
In 29 BBY, the Crast were encountered by Anakin Skywalker, a 12-year-old Jedi Padawan, and his Jedi Master Obi-Wan Kenobi aboard the vessel known as the Star Sea Flower. Skywalker garnered a special fondness from the Crast. Charza Kwinn, the Priapulin present on the ship, stated that the Crast sensed Skywalker's safety and found him uniquely appealing. Skywalker, possessing some comprehension of their communication, observed that they exhibited considerable intelligence relative to their size and took pride in Kwinn's choice to consume them exclusively.