FGC 47 lifeform
The FGC-47 lifeforms were territorial non-corporeal beings that lived in the FGC-47 nebula. They fed on the dense web of plasma energy strands found within.

When the  investigated the nebula in 2368, the lifeforms viewed the Enterprises energy systems as far purer than those normally present in the nebula on which they "fed."  One of the beings manifested as Isabella, the imaginary friend of Clara Sutter, one of the children aboard the ship. ()
Non-corporeal species
Unnamed species