Bat-like flying animals living in the caverns of Celtris III, which startled Picard's covert team during their search for a suspected Cardassian weapons laboratory.
Lynars are winged, bat-like creatures that roost in the cave systems of Celtris III, an uninhabited planet in Cardassian territory.
They appear in Chain of Command, Part I. Picard, Worf and Beverly Crusher descend into the caverns on a secret mission to find and destroy a laboratory believed to be producing metagenic weapons. As they move through the tunnels a swarm of the animals bursts out of the darkness around them. Crusher is badly startled; Worf calmly names them as lynars and says they are harmless.
The moment of relief is brief. The laboratory does not exist, the mission is a trap baited for Picard, and he is captured while covering his companions' escape.