The Squire of Gothos

In Space Quadrant 964, eight days away from Colony Beta Six, the Enterprise is trapped in orbit around an uncharted planet. There, Kirk and company are confronted by Trelane, an illogical but extremely powerful alien. Although he appears as an adult humanoid, Trelane is eventually revealed to be a ``child'' belonging to an unknown, alien race. Trelane's parents rescue Kirk and the Enterprise from their playful son.