This is a real molecule! It is a protein found in the saliva of vampire bats and is an anti-coagulant that is 100 times stronger than the anti-coagulants used in medicine.
Image kindly reproduced according to the licence at: http://en.wikipedia.org/wiki/File:Desmodus.jpg
The bat uses it to stop the blood of its victim from clotting whilst it is drinking.
For more information, click here: http://en.wikipedia.org/wiki/Draculin