Urban Legends: Steop

In Gelderland, Netherlands roams a creature called the Steop. It's a wolf-like terror and is known to torment people. He is known to jump on the back of people and grow increasingly heavy. There is no way to get him off of your back and will do this for hours. He is also known to make things disappear and watch people stress about the missing items. 

SOURCES:

Dutch Folklore Wiki