The larval form in the sandworm lifecycle of Arrakis, also called 'little makers'. Sandtrout are flat, leathery creatures that encyst water deep beneath the desert surface, creating the arid conditions necessary for the adult sandworms to survive. They also produce the pre-spice mass that eventually becomes melange. Leto II merged with sandtrout to begin his transformation into the God Emperor, their symbiotic membrane giving him immense strength and near-invulnerability. The sandtrout-sandworm lifecycle is the key to understanding both the ecology of Arrakis and the production of the spice.