A small Teenaxi accidentally beamed aboard the USS Enterprise after a failed diplomatic mission in Star Trek Beyond, who stays on with the crew and turns up at Kirk's birthday party.
Kevin is a member of the Teenaxi, a species of small, ferocious creatures seen at the opening of Star Trek Beyond in 2263.
Kirk comes before their assembly to present an ancient artefact as a peace offering from their enemies the Fibonans. The Teenaxi take the gift as an insult and swarm over him, and when Scotty beams the captain out, two of them are carried up with him.
One of the pair, known as Kevin, evidently remains with the crew. He survives the destruction of the Enterprise at Altamid and is seen at the surprise birthday celebration for Kirk on Starbase Yorktown at the end of the film, where Kirk observes that he has acquired a blue uniform shirt but still wears no trousers.