They are two Forest Elves who are old friends with Cosmo and Wanda. They speak enjoy speaking in rhyme, much to the annoyance of Cosmo and Wanda. They seem to be a bit annoying in general, as Wanda states she remembers why they stopped hanging out together after spending a bit of time with them.
They both seem to love Bocci Ball and get very competitive over it.
They are both shorter than Timmy and Chloe. Mindy has straight neck length neon blue hair, similarly colored eyes and curved buck teeth. She also has a flower sticking out of her head. She wears a pink whit dress and purple shoes.
Mo, on the other hand, has a leaf sticking out of his head and straight buck teeth. he has flat light brown hair with a darker shaggy goatee. His clothing is purple with black shoes.
They both have buck teeth, plants growing out of the top of their heads, large pointed ears and their clothes don't have any sort of straps or support at the top.
They both appear in the episode Spring Break-Up, where they are seen living in a cookie tree. The fairies recognize them as old friends and begin to play a round of Bocci Ball with them, while Timmy and Chloe go off to eat more of the forest, as the forest around Mindy and Mo's house is made primarily of food.
While Forest Elves have appeared since the Spellementary School episodes in earlier seasons, these are the first and only ones that have a major role in an episode.