A tenticle-like creature which has a proclivity to violate the rectal region of humans. It has the twin abilities of being able to sense the human butt from long range and the ability of burrowing straight through solid walls made of any material. Very dangerous, but not lethal, the wallshark is able to find anyone anywhere and summarily violate their bottom. The only way to sense their presence is by using advanced precocknition
There are many variations of wallshark, including the thick and dangerous Euopean, the tiny, but numerous Asian, and the long living African type. With modern trade, it has become very simple for these types to migrate and interbreed. One day we will shall have a super wallshark on our hands with no way to stop it. It will be worse than whales on stiltand a dark day indees.