Apollo was the last survivor of an alien super race who captured the USS Enterprise and tried to force its crew to worship him. He committed suicide when they refused and destroyed the source of his power. He appears only in the episode "Who Mourns for Adonais".
Apollo was visually indistinguishable from a human, and he registered as largely the same on Dr. McCoy's medical scans, the only difference being a unique organ believed to be related to his superhuman abilities. These superhuman abilities included the following:
- Generating telekinetic forces strong enough to immobilize and damage a Constitution-class starship. He was able to apply such forces from at least orbital ranges.
- Generating electromagnetic discharges capable of rocking the Enterprise and easily killing an unprotected human.
- Projecting images of himself.
- Altering his own size.
- Manipulating the weather of the Earth-like planet Pollux 4, on which he dwelled.
- Superhuman life expectancy of at least thousands of years and possibly unlimited.
The exact nature of Apollo's power was unclear, but it was apparently generated from a Greek temple on the planet's surface. His power was presumably diminished when the Enterprise destroyed the temple from orbit with sustained phaser fire. Following its destruction, Apollo "spread himself upon the wind", growing to immense proportions and then fading away.
Apollo greatly desired to be worshipped, claiming that he required adoration as "mortals" required food. He was willing to employ bribery and threats to achieve his goal. He apparently had the power to destroy the Enterprise, but chose not to do so when pressed, attempting to intimidate the ship's crew instead. When they refused to submit, he apparently chose suicide over a "mortal" existence.