Photonic fleas aboard Voyager
Photonic fleas are tiny flying insects native to the Delta Quadrant. They build flimsy webs and feed on plasma particles.
A mating pair of photonic fleas were inadvertently brought aboard the USS Voyager in 2376 within a shipment of amber spice. The insects nested near a plasma conduit, causing a momentary loss of sensor resolution whenever they tapped into the conduit for nourishment. They were moved to a safe location after their discovery. (VOY: "The Voyager Conspiracy")