Out of the Abyss
Stool resembles a large mushroom, trundling around on trunk-like feet. As the only non-humanoid creature, he is lonely and frightened.
Stool is a native of Neverlight Grove, a utopian settlement of Myconids to the southwest of the Darklake. The Myconids there have carved out a relatively peaceful existence, tending their fungi farms and living as a single commune. They are largely left alone by other denizens of the Underdark. Stool wants desperately to return there.