Subspace-dwelling beings native to the lower atmosphere of the gas giant Marijne VII, trapped aboard the stranded USS Raman, one of whom appears to Geordi La Forge as his mother.
These beings live deep in the turbulent atmosphere of Marijne VII and cannot survive for long at higher altitudes. They have no solid form that the Enterprise crew can detect and seem able to contact a humanoid mind only through direct neural stimulation.
They appear in the Next Generation episode Interface. The science vessel Raman takes some of them aboard by accident while sampling the atmosphere and then climbs away, and their efforts to communicate kill the whole crew. La Forge explores the wreck through a probe linked to the neural inputs of his VISOR, shortly after hearing that his mother, Captain Silva La Forge, is missing with the Hera.
One being takes her likeness and begs him to bring the ship down. Geordi finally realises what it is, flies the Raman lower against orders, and the beings return home as the ship breaks up.