Winged, plant-based flying creatures native to the planet Phylos, used by the Phylosians and Dr Keniclius to seize members of the Enterprise landing party.
Swoopers are airborne plant creatures seen in the animated episode The Infinite Vulcan. They live on Phylos, a world where the dominant life is vegetable rather than animal, and resemble purple, bat-winged dragons trailing long tendrils.
When Kirk, Spock, McCoy and Sulu explore the planet, a flock of swoopers attacks, wraps the officers in its tendrils and carries them off. They are brought before the giant clone Dr Keniclius 5, who keeps Spock as the template for a race of peacekeepers he means to impose on the galaxy.
The creatures serve as the muscle of a world whose native Phylosians were all but wiped out by a disease the original Keniclius brought with him, and whose fleet of ships has stood idle ever since.