Onaya was a non-corporeal being that could assume corporeal form. It both increased exponentially and fed off the creative energy generated by the stimulated brain of another being. The process usually proved damaging to the subject being stimulated, as the strain of increased capillary dilation, neurotransmitter production, and general neural activity would cause synaptic collapse and, if left untreated, death. Onaya justified its activities by saying that victims would receive immortality for the creative ventures that were a byproduct of its activities.
It had traveled for thousands of years seeking compatible creative beings, and found hundreds such as the Earth poets Catullus and John Keats, the Cardassian architect Tavor Kell, and Tarbolde from Canopus Planet. Onaya could be detected by tricorders set to scan for psionic energy residue.
Onaya visited Deep Space 9 in 2372 and fed off the creative energies of Jake Sisko as he was working on his first novel, Anslem. Jake's life was saved when his father, Benjamin, intervened. Onaya, however, was able to escape from the station, vanishing into the unknown. (DS9: "The Muse")