A mythical creature, very dangerous in both violent and sexual ways.
(It's name derived from its giant sexual organ the schlone.)
If you get too close to a slonebacker that does not like you, it will rip you to pieces and feast upon your genitals and private parts.
If you get too close to a slonebacker that does like you, unless you have informed it of not being sexually active with slonebackers it will,
In a man's case: stick its schlone in your ass amd rip with such force not many survive.
In a woman's case it will mount her backside only, and shove its schlone in the most general areas much like a human would do.
I read once about a schlonebacker in a fairy tale, the hero was the last warrior that had not been anally torn by the schlonebacker and was able to defeat him.
He made a war trophy from the Schlone of the schlonebacker