Feared by man and troll alike, the Cat on the Droskarsfjell is as large as the wooly mammoths of the Golden Steppes, and as wild as the roaming lynx of Slitimark. It’s origin is unknown, but the tale of the greedy cat that ate the goodman and the goody, and Lady Moon in the sky, and Lord Sun in heaven and all inbetween is surely inspired by this horrid feline. Instinct: to consume

• gobble them up
• Consume something ephemeral, like warmth or light
• Appear silently, suddenly
• Toy with its prey

Fossegrimen is a lonely creature, but an expert fiddler. If you bring him a worthy sacrifice, preferably a a white he-goat thrown with head turned away into a waterfall that flows northwards or a lucious fenalår (smoked mutton), he'll teach you how to play a tune so sweet that tables and benches, cup and can, gray-beards and grandmothers, blind and lame, even babes in the cradle will begin to dance.

But beware, if the goat is too scrawny or the fenalår picked clean, he'll be less than pleased.
https://en.wikipedia.org/wiki/Fossegrim Instinct: to enthrall

• receive a worthy sacrifice in return for his teaching
• a dangerously catchy tune
• reject a unworthy offer spitefully

The farmers up in the valley tell of a particularly vicious bear. Whole flocks of sheep torn asunder. The belly of old Svitun's daughter ripped out. How Aslak, the boy on the neighbouring farm, was found wandering confused in the forest, clothes ripped asunder, twigs in his hair. And he was fixing to be a father come spring, now both babe and soon to be wife was taken from him. Instinct: to rage

• Hug them tight and don't let go
• spread the curse
• Crush and maul
• Change form

The symbiotic jelly exists by controlling the mind of another creature, which it then uses for protection and to obtain sustenance.
These creatures choose unoccupied caves in which to dwell, and stick to the ceiling in the shadows, where they are almost impossible to detect. When a carnivore ventures into the cave, the symbiotic jelly will attempt to use its innate charm monster ability to persuade the intruder telepathically to remain in the cave and attack any other creature which enters.
Thus, if a huge cave bear is charmed, it may be made to appear as a weak bear cub, while the back of the cave might appear to contain a rich vein of gold ore if a dwarf entered the cave, or a sumptuous banquet if a hungry halfling wandered by. Instinct: to feed of carnivorous instincts

• Read your desires
• provide what you want the most
• make its host appear harmless and weak

Caterwauls are vicious feline creatures with short, midnight-blue fur, yellow eyes and a long, prehensile tail. The face has an almost elven look, with its delicately pointed ears and almondshaped eyes.
The caterwaul’s preferred method of attack is to hide in a tree or rock outcropping above a trail and leap onto its victim, chasing it only if necessary. Caterwauls are able to move on their hind legs at great speed, then drop to all fours to move even faster.
The caterwaul is normally a militantly solitary creature, leaving its mother after only three months of life. The normal lifespan of a caterwaul is 5 years. During its life it will breed a maximum of three times. Caterwauls do not mate for life, as this would necessitate a permanent companion.
Caterwauls are generally found in low mountains, especially those with thick vegetation. Like most felines, the caterwaul hates water, but it can swim if necessary. Its diet is exclusively meat, generally large rodents, but larger prey is not uncommon, and it will occasionally supplement its hunting with a raid on domestic sheep or cattle. After killing something the size of a sheep or larger, the caterwaul will gorge itself, and then it may not hunt again for up to ten days. It will, however, defend its territory at any time from all intruders. The caterwaul is not a scavenger, and will not even finish off its own kills if they are more than a day old.
The caterwaul’s prehensile tail is of little use in combat, but the creature will often use its tail to secure its food for eating. It will also use it as a sort of “hand” to brush twigs or other obstructions out of its line of sight when it is waiting in ambush. Like most cats, the caterwaul’s tail is also an elegant indicator of the creature’s emotions. Ecology: Caterwauls have no natural enemy, including man. They hunt only for food, and fight to defend their territory. The claws of a caterwaul may be used in the creation of a sword of sharpness. Its fur is prized for its unusual color, but must be carefully treated to remove the caterwaul’s scent.
Converted from AD&D Fiend Folio
Instinct: to gorge itself

• Unleash a earpiercing screech
• Climb virtually any surface
• move with prenatural haste
• Approach unheard