Recently a selection of volumes of Magia Naturalis (in English, Natural Magic) twenty volumes came up for auction in an estate sale. These parituclar volumes were vary dangerous due to the annotations and notes written within them by a monster hunter and sorcerer. Sir Charles Baptist was an amateur hunter and adventurer of renowned who had acquired these volumes from his old family mansion in the upper part of New York state. These volumes dated back before the forming of America itself, and the family's interactions with legendary creatures including the Mythos but these volumes also contained wards, counter spells and weird incantations dating back centuries. Some of them quite dangerous to the soul & sanity of their caster.
More about Magia Naturalis can be found right over HERE
Henry Wallis was an naturalist and occultist of some repute who lusted after these volumes for years and had a friendship with Sir Charles who contracted a deadly jungle disease after a particularly harrowing experience in the bush of Africa.
Wallis managed to secure the volumes of 'white magic' and pre-Baconian science, one paritcular aspect of these volumes was the the tales of Wha Baccuum, a dark and dangerous primordial world in another dimension. This world of incredible beauty was only surpassed by the viciousness of its prehistoric inhabitants. Wallis managed to open a dimensional rift to this world and for his troubles the experience killed him. The rite was cast at a near by lake and a Chaousarou of dangerous aspect was summoned. The creature not unlike others of its kind quickly adapted to its environment and has begun to feed on locals and some live stock. It is quite clever in its feeding patterns and bares an almost uncanny malicious intelligence.
The PC's are called in as 'experts' by the local police knowing that they are in far over their depth. The characters are well known as 'experts' in matters of the occult and such. Wallis's corpse has been found near the lake shore still dressed in his robes and surrounded by accutraments and instruments of the occult. A single volume of Magia Naturalis lays near by covered in close cropped cryptic writings that the Baptist family used. There is a very uneasy feeling surrounding the area as if something dark and dangerous is watching.
The police have Wallis's apartment coordinated off and the PC's can get first crack in. The apartment is a fairly standard 1920's flat and for a raging occultist's residence is fairly well kept accept for the kitchen table which is covered in volumes of notes practically thousands of close worked handwriting similar to the type found within Magia Naturalis. The books themselves are scattered about as well, stuffed with hundreds of notes & scribblings. There is also a diary by Wallis written in archaic Dutch that has the cipher key written within it including his mad plans.
Reading all of the ravings of this mad mind will cost 1d10 points of sanity as Wallis's mind breaks under the strain of the occult concepts of dimensional walls and insane passages to primival worlds. Places where the Elder Things still might hold complete sway over the passage of life and death. 
Wha Baccuum is such a world and a source of incredible magickal power. Wallis thought that using the dark powers in charge of this world would make him like unto a god.
The Chaousarou will have killed eight to ten people by the time the invesigators come across the rite to return the horror to its world. Eventually after the third new moon, the dimensional shift will hurl the monster back to its own space time but who knows how many people it will have killed by then. Gain 1d10 minor spells and rites as well as the correct spell to banish the Chaousarou back to its home world.
STR 36
CON 30
SIZ 40
POW 15
DEX 8
Move 10 Swimming
HP 35
Damage Bonus: +4d6
Weapons:
Bite – 95%, 2d6 + Damage Bonus
Armor: 6 points
Skills: Watery Stealth 65%, Spot 55%, Listen 70%.
Sanity Loss: Lose 1d2/1d6 Sanity Points on seeing A Chaousarou.
Capsize – A Chaousarou can spend an attack action to capsize a rowboat, canoe or other small watercraft by rolling its SIZ or less on D100. If it succeeds, the boat is overturned.
Death Roll – A Chaousarou that scores a special hit with its
To learn more about the Chaousarou, visit Clint Staples blog right over HERE
Or pick up the Mythos Society Guide To New England for a ton more solid old school Call of Cthulhu information.
Available right HERE
Note that this adventure encounter could easily be translated into a wide variety of horror retroclones with little issue.
