A muse is a personification of the imagination, and a source of motivation for artistic and scientific output. They also seem to act as a kind of soul compass, offering words of advise when their owner is troubled. It is believed that every person has one in some form, though not everyone is aware of it, or has yet to tap into it. At least one so far has shown the ability to shapeshift.
Mort's Muse Edit
The Embodiment of Science is a constant Go-To source for Mort whenever he is troubled, which means she is frequently called upon to bail him out of a moral quandary. As a scientist, Mort does not believe in superstition or magic, so the existence of a muse is at first a shock to him. He quickly warms up to her and accepts her, however, and follows her advise. This quick acceptance could be seen as unusual, but since Mort doesn't really believe in himself an awful lot and yet he exists anyway, he figures why not a figment of his imagination? After all, he invented it, even if he didn't. Yes, this confuses him too.
Mort's muse has displayed the ability to shape shift, taking on different identities. Her first appearance is that of the Great Gazoo. This apparently displeased Mort, so she assumed the role of a sexy female Starfleet Officer from Star Trek. This caused Mort to be delighted. So far Mort's muse has shown incredible insight into Mort's troubled mind, offering concise and accurate advice and helpful words of encouragement. She could be seen as an aspect of his procrastination, as she has at least once told him to go play outside rather than work on his projects, though this could be seen as an active way of getting him to feel more motivated by letting his hair down and taking a healthy break.
Gar's Muse Edit
Gar's muse is a personification of Princess Sally Acorn, a Princess from the Sonic the Hedgehog universe. That, or Gar is somehow able to reach behind his back and pull out individuals from their respective universe. She has only had one appearance so far, and is currently the only form she has adapted. This could be because of Gar's secret love of naked talking squirrels with a blue taste in fashion. It is yet to be revealed just how she motivates Gar, and how this affects him.
So far the Princess has shown no specific abilities. She has, however, demonstrated her adorable cuteness and mastery of the word "Yo". She has great taste in fashion.