Flat, two-dimensional lifeforms that swarmed the Enterprise while migrating toward a cosmic string, dragging the ship along with them.
These creatures exist in only two dimensions, so the Enterprise sensors could barely detect them. They travel in large groups and are drawn toward cosmic strings.
In The Loss, a swarm trapped the Enterprise and pulled it toward a cosmic string, where it would have been destroyed. Their presence also cut Deanna Troi off from her empathic sense. Troi realized the creatures were drawn to the string like moths to a flame, and the crew used the deflector to imitate the string's signature, letting the ship break free.