Grimrock

“Black Shadow Horror Beast”
This (animal/horror) monster can be found lurking through abandoned mines and ancient crypts. Very rare and usually only found in isolation or living amongst horrifying insects and creepy crawlies. It is not considered part of The Watcher’s Army. Very rarely, The Watchers take one of these beasts as a pet for experiments or protection... and The Watcher’s have learned many dark things from such occasions, however, it usually ends badly as these beasts are somewhat intelligent and almost impossible to contain safely. It looks very similar to a Balrog (Lord of the Rings) (without the fire or weapons) crossed with a darker version of ‘Beast’ (Xmen). This monster is cloaked in darkness and shadow... sometimes only its eyes being visible from a distance. It can launch itself and charge at the party from the cover of shadows (hopefully scaring the shit out of the player), swiping at its prey with razor sharp claws... If need be, it can cast the darkness spell... dispelling all kinds of light sources – using this as a means of stealth and or escape. Also, while covered in darkness, it can slide through shadows (teleporting itself) and emerge from other shadows nearby. Overall, the player should feel scared, uncomfortable in the dark and preyed upon when facing this monster.