Ultraspice referred to the extremely potent spice produced by the internal organs of seaworms.
Created by Waff[]
Seaworms were genetically altered sandworms produced by the ghola of the Tleilaxu Master Tylwyth Waff while aboard a Guild heighliner, which was also being used as a research ship. Waff successfully stopped the altered sandworm from turning into a water-imploding creature, and instead turned the creature into one which naturally lived in deep oceans.
To test the success of the seaworms, Waff had a group of seaworms delivered to the ocean world of Buzzell. Not only did the seaworms survive in the seas of the planet, but they thrived and quickly dominated the eco-system; displacing and eating the native cholisters, and the half-fish/half-men Phibians.
During his last research visit to Buzzell, Waff and his Guild assistants caught a seaworm, and began to dissect it. Inside of a liver-shaped purplish organ was a cache of pure ultra-potent spice, which was quickly dubbed ultra-spice. Waff gave the ultraspice to the Guildsmen, who delivered it to the Navigator Edrik. Khrone, and his group of Enhanced Face Dancers, representatives from the Administrator branch of the Guild, stole the Ultraspice from, and killed Edrik; and destroyed his ship. Secretly, Khrone took the ultraspice to Synchrony, and delivered it to the Thinking Machine rulers, Omnius and Erasmus.
Paolo on Synchrony[]
Concurrently, the no-ship, the Ithaca, was captured by the Machines and brought to Synchrony, as well. The Machine leaders believed that the end of the age, or Kralizec, was upon the galaxies. To strongly influence this universal change in their favor, they wanted to capture the Ultimate Kwisatz Haderach, whom Erasmus' complex "mathematical projections", showed to be on the Ithaca. As a back-up plan, they had secretly, 13 years earlier, created a clone of the first super-being, Paul Atreides, whom they named Paolo. They had him brought up and trained by Vladimir Harkonnen for a cruel personality, and Erasmus trained him in fighting skills.
As the teenage ghola of Paul Atreides was captured on the Ithaca, and brought to the capital of Synchrony, the Cathedral; so too, was Paolo brought to the heart of the Machine World-city. Omnius announced that Paul and Paolo would fight to the death, and the winner would be given the cache of ultraspice. Paolo near-fatally wounded Paul, and was declared the winner of the duel. Paolo quickly imbibed a huge portion of the super-potent melange, and found his prescience increased to super-human levels. Paolo quickly found that the ultraspice caused his prescience to go into a type of overdose, and he fell into an irreversible trance-like coma, and ended up starving and thirsting to death.
It is not known if ultraspice was ever used again.