A Moomintroll is a creation of Finnish
author Tove Jansson, and the
title character of a
series of books that she wrote for children. It's a modern
fairytale, really; set in
fantasy forests of Finland (oo, that
scans!). As to what, precisely, a Moomintroll is, I present:
"A Moomintroll is small and shy and fat, and has a Moominpappa and a Moominmamma. Moomins live in the forests of Finland. They like sunshine and sleep right through the winter. The snow falls and falls and falls where they live, until their houses look like great snowballs. But when spring comes, up they jump...."
- Kaye Webb, editor of Puffin Books 1974.
I strongly recommend these books for grade-school readers. This information comes from the following webpage, which I recommend you see for more info on the books: http://www.io.com/~fazia/Moomin.html