You need to:
Just leave a comment naming your favourite or most unfavourite, real or made up, living or undead, horror creature. One word will do it, although feel free to wax lyrical on why you like, or despise, your chosen subject. Please, keep it nice though, or you will be deleted. You don't have to come up with a little known subspecies of Mesopotamian werewolf or an obscure Aztec revenant who haunts the world for all eternity. A bog standard comment like 'I rooly trooly heart zombz' will do, even if many others have already written this. You can even be specific and name names if you prefer e.g Dracula. Don't sweat it, just participate, then cross your fingers.
Head on over to Gitte Christensen's blog if you want to try your luck.