Abeloth

Abeloth is a creature that Luke Skywalker encounters in the Maw while searching for reasons behind Jacen Solo's fall to the dark side.It is also hinted that this is the presence Ben Skywalker felt while he was kept at the Shelter,causing him to turn from the force.

In the Font of Power, Luke encounters the ancient evil, that takes the form of a woman -- "with a large full lipped mouth so broad that it reached from ear to ear. her stubby arms protruded no more than ten centimeters from her shoulders and in place of fingers, her hands had writhing tentacles so long that they hing down past the rim of the basin."