[olelele]

There is an enormous difference in tone if you actually read any of Tove Janssons books. The animated moomin series is childish and cute. The world of the books is dark and scary and contains monsters and threats that are almost lovecraftian. The moomin trolls are victims to their surroundings and the forces of nature...

[internet_points]

Some of the animated adaptations were freakier than others: https://www.youtube.com/watch?v=aVQlJDtzUbo

(And even the books, floods and comets, children's books about impending natural disasters, not of the magical kind that you know aren't real anyway, but of the kind that have actually destroyed life on earth before and might happen again, that's real nightmare fuel for active children's imaginations.)

[vidarh]

At least one of the adaptations as of the 1980's also had moments that were very much dark and scary as a child. I haven't read or seen anything of the Moomins since, but I think the Groke might have been one of the things that freaked me out.