Omwanar

The  were a species that resembled Earth jellyfish, except that they were six feet tall. Their tentacles secreted a neurotoxin that was fatal to humans. They were paranoid and isolationist.

In the 30th century, the Human-Omwanar war was waged, lasting for ten years. A peace treaty was signed on 23 April 2978 by Lyshur Lysus for the Omwanar and Steven Taylor, pretending to be Space-General Sir Robert Simmons, for the humans. (PROSE: Making History)