My Little Pony: Friendship is Magic, book 43: Ponies of Dark Water
Thom Zahler et Tony Fleecs2016

'Ponies of Dark Water Part 1' The Ponies go on an adventure to a newly erupted geyser. After some fun playing in the water, the ponies begin to act a bit strange, perhaps even… sinister? What happens when good ponies turn bad?

Titre original : My Little Pony: Friendship is Magic, book 43: Ponies of Dark Water (2016)