Q: What does Mokona eat?
A: Mokona eats cinnamon buns and fruit--the latter we see Mokona about to eat at a picnic with the Magic Knights, but not take a bite out of. At least, that's what we see in the anime. Mokona doesn't need to eat at all in the manga.

Q: What is Mokona made of?
A: it's unknown. Marshmallows? Something bouncy for sure!

Q: Is Mokona male or female?
A: That's not revealed, but Fuu does refer to the critter as "Sir Mokona". Others refer to Mokona as he, she, or it. Perhaps it really doesn't matter anyway.

Q: Can Mokona fly?
A: Although Mokona's main method of getting around is to hop, the critter can stay airborne for a short time by flapping its ears. Mokona does produce flying vehicles, the second of which is seen in the manga, for people to travel large distances. Manga spoiler: Click for more information.

Q: Who does Mokona belong to?
A: Mokona, according to the manga, belonged to Princess Emeraude. She instructed Clef to give Mokona to the Magic Knights. Clef then left Mokona with Presea and told her to let the Magic Knights have 'em.

Q: Why does Mokona's forehead jewel change color?
A: When communicating with Clef, Mokona's jewel changes to a color "suited" to that person. For example, Umi's elemental color is blue, so the forehead jewel turns blue in order to speak with Clef. Spoiler: Click for more information.