Normal sudoku rules apply, but strange things are afoot.. Creatures of the night have invaded the land! Each row, column and box contains one creature, marked by a coloured dot. All creatures are marked. Cells containing a creature ‘index’ either the row, column or 3x3 box number (read in normal reading order) they're placed in. Each number assigned to a creature is unique and can't be repeated. Marked by a green dot, zombies have an infectious bite ie orthogonally adjacent cells are even when the zombie's number is even, or odd when the zombie's number is odd. Marked by a grey dot, poltergeists throw everything into disarray ie orthogonally adjacent cells are either all higher than the poltergeist's number, or all lower. Marked by an orange dot, horsemen have a knight's reach ie Cells a chess-knight's move away from the horseman can't contain the same digit as the horseman's number. Marked by a red dot, vampires suck the power from their victims ie Orthogonally adjacent cells sum up to the vampire's number. The land is covered in fog. Placing correct digits will lift the fog. No guessing is required. The monster under your bed will know if you cheat!