Age-ray

The age-ray was a device which could reverse the age of its target, from a few months to several years. The speed of the de-aging could be adjusted from instantaneous to over a period of a few hours.

The age-ray was constructed by Laiko, a scientist on a Trann starship which had crashlanded on a planet in Galaxy Zekbran. Intended to restore power to the ship's engines, its true function was revealed when it accidentally de-aged the crew's pet. Realizing they could use the ray to halt their aging so they could live long enough to repair their ship or be rescued, they decided to test it on members of an USS Enterprise landing party, which de-aged Burns and into children, Leonard McCoy into a teenager, and James T. Kirk by a few months. After the test was finished, Kooba attacked Laiko and took the ray back to his ship, where he seized command of his crew and de-aged the one crewman who objected. He revealed his plan to use the age-ray to return to his home world and conquer it by de-aging the members of government. After de-aging the Enterprise crew, Kooba attempted to de-age Kirk into a baby, but Kirk used a metal plate to reflect the beam back, causing Kooba to suffer this fate instead. After returning the Enterprise crew and the Trann crewman to their proper ages, Kirk smashed the age-ray.