The earliest stage of metamorphosis for the Sand Worm. The Sand Trout is released in a Spice Bloom and from there performs its sole purpose of trapping water in the planets core, deep enough so as it cannot harm the Sand Worms. A Sand trout is small enough to fit in the hand of a child, one Sand trout can be grasped in the palm, however Sand trout function in groups. Sand trout are strong creatures and much stronger so when interconnected in a group organism. They are extremely resilient with a leathery skin and capable of moving at high speeds through the sand (relative to their size). Their organs are extremely keen and can sense as little as one drop of water from extremely far distances.
In the desert the Sand trout are known as good source of water when in need. They can be drawn to the surface with a small amount of water and when/if captured their water supplies can be sucked out of their body. The amount of water in an individual Sand trout is usually very little, for that reason this technique is rarely employed except in desperation and by small Fremen children as a game.
It was Leto II, who would one day become known as the God Emperor, who as a child made a commitment to the Golden Path which started with a genetic and chemical change of his body allowing him to become part of a Sand trout group organism. This new organism had all the strength and agility of Sand trout but in human form. The Sand trout became his skin. These new abilities allowed him to dethrone Alia, his Aunt. These event were the first and vital steps towards the death of Arrakis, the Scattering, the God Emperor and everything that is the Golden Path.