Fetus

Not an age writers commonly write about, but perhaps the adventures of a psychic fetus could be funny?

Alternatively the character may be an unborn child. Narration of the unborn child's character could be through the mother, father, or those who interact with the pregnant woman. Mothers (and grandmothers) in particular tend to assign many characteristics to their unborn children whilst still in the womb, and perhaps this is how an unborn child's character could be developed in writing.

Lastly, from a political side of things, one could write about the feelings of a fetus in regards to abortion. Perhaps writing the story from the point of view of a fetus?