Enormous creatures that live in open space near Alpha Omicron, one of which the Enterprise accidentally kills before helping to deliver its unborn young in Galaxy's Child.
These spaceborne lifeforms appear in the Next Generation episode Galaxy's Child. In 2367 the Enterprise meets one in orbit of the seventh planet of the Alpha Omicron system. The creature drains the ship with a damping field, and a minimal phaser burst fired in self-defence unexpectedly kills it.
Data then detects a second energy reading inside the body. Crusher uses the phasers to perform a kind of caesarean, and the newborn, nicknamed Junior, imprints on the Enterprise, fastens itself to the hull and begins feeding on the ship's power as though nursing.
La Forge and the visiting engineer Dr Leah Brahms work out how to wean it. They change the frequency of the energy it is drinking, in effect souring the milk, and Junior lets go to join others of its kind in a nearby asteroid field.