the Seaweed-horse :

You are a fisherman on an irish lake. Yours worst fear : to come face to face with an seaweed-horse. This creepy creature looks like a giant horse with seaweed on his mane. Every fishermans carry everyday their own toxic mushrooms coming from some australian koalas. In fact, they want intoxicate seaweed-horses with this mushrooms, because they are crazy about it.
The monster of the Loch Ness is probably a seaweed-horse !

This horse is a star : it appears in Fantastique Animals 2 for example :