Isabella was the imaginary friend of Clara Sutter, one of the children aboard the Enterprise-D. When a spaceborne entity came aboard the Enterprise in 2368 to investigate the ship as a potential energy source for its race, it appeared in the form of Isabella and befriended Clara. This was also an attempt to understand the nature of those living aboard the Enterprise.
However, the entity acquired a misunderstanding of the Enterprise crew, as it was learning about them from the perspective of a child. When Clara was told to stop communicating with the entity, it and others like it began to draw power from the Enterprise's shields, which threatened to destroy the ship. However, the entities would depart when the one that had assumed the form of Isabella was made aware of its error in judging the crew and of its negative impact on Clara.
Before departing, however, the entity appeared one last time to Clara in the form of Isabella, expressing its hope that they would one day see each other again. (TNG: "Imaginary Friend")
- Isabella was played by Shay Astar.