Energy being

Energy beings are entities of pure energy. They are aliens who have evolved beyond their physical bodies and are from another dimension who are "big on musical theatre". They have a electro-quantum structure which the Planet Express crew thought could be overloaded, but instead makes them grow.

It is unknown if Melllvar and his mom are the same species as M5438, but based on their dissimilar structures, this seems unlikely.

Trivia

 * They are based off the many in Star Trek.