Salusan Bull

Salusan bulls are bovine animals native to Salusa Secundus. Their backs are covered with spines, their heads are black studded with multiple horns, and have faceted eyes. They have two separated brains.

A particularly fierce creature, Salusan bulls were kept in Caladan. Stablemaster Yresk tended the bulls for Duke Paulus Atreides for his occasional spectacles; however a Salusan bull was responsible for the death of Duke Paulus Atreides. After the Old Duke's death, the bull was slain.

During the reign of Leto the Just, the bull's head was mounted and hung on the wall of the Atreides dining hall, firstly on Caladan, then on Arrakis.

Behind the Scenes
Conceivably, this creature was one of the dangers that Imperial Sardaukar experienced when being raised on the harsh environment of Salusa Secundus during their training, and may have contributed to the high mortality rate experienced during their upbringing.

Apocrypha
The Storyboard art for Jodorowsky's 1974 adaption by Moebius depicts the Bull as a rhino-like creature.