ACANTI

Benevolent and compassionate by nature, The Acanti are a species of peaceful sentient kilometers long  reddish brown whale-like, space-faring extraterrestrial beings. They possess dorsal, ventral, lateral, and caudal fins, as well as green eyes widely spaced on their heads.  They communicate through psionic sounds referred to as songs. Acanti have the innate ability to fly faster than the speed of light, without technological assistance.

A long time ago, the Acanti were led by one individual known as the Prophet-Singer. The Prophet-Singer was the repository of the Acanti's racial Soul, a collective semi-mystical force that linked and motivated the Acanti species. As death approached, the Acanti typically hurled themselves into stars. The Prophet-Singer of each generation would also do so, releasing the Soul to join the body of the next Prophet-Singer.

Upon migrating to the Milky Way galaxy, the Brood species began to enslave the Acanti to take advantage of their natural ability to travel at speeds exceeding light. The Brood would infect individual Acanti with a disease known as the Slaver Virus, which would destroy the higher cognitive functions of their minds, making them ripe for easy control. Then, the Brood would transform the mindless husks into living starships. The Brood succeeded in enslaving the Acanti Prophet-Singer, and when he eventually died and crashed on a planet, its body was reconstructed as the "throne city" (presumably like a capital) on the planet (referred to as "Broodworld" or "Sleazeworld") that the Brood then established as the center of their empire. Thus, the Soul remained trapped in the skull of the dead Prophet-Singer.

Salvation for the Acanti came when a new Prophetsinger was born, however, without transferring the soul to him, the Acanti were still stuck near Sleazeworld. Only when the SOul was freed by external intervention in 1982 did the Soul unite with the young Prophet-Singer, who assumed leadership of the Acanti.

Source: Marvel Universe.  Uncanny X-Men #156 (April 1982) They were created by writer Chris Claremont and artist Dave Cockrum.