Inhabitants of chaotic space, a zone where the laws of physics shift constantly, who reach Chakotay through hallucinations of a boxing match in The Fight.
The aliens of chaotic space appear in the Voyager episode The Fight. Chaotic space is a wandering region in which physical constants are in flux, so that sensors and engines cannot be relied on, and ships caught in it are usually crushed.
In 2375 Voyager is trapped in one of these zones. Its inhabitants are so unlike humanoids that ordinary contact is impossible. They can, however, stimulate a gene in Chakotay linked to a hereditary tendency to hallucinate, and they speak to him through his own memories. He finds himself in a boxing ring facing an opponent called Kid Chaos, with his old trainer Boothby in the corner and the voice of his grandfather in his head.
Chakotay fears he is going mad, as his grandfather seemed to. With the Doctor's support he stops resisting, takes in the aliens' instructions and pilots the ship out.