From publisher blurb:
Unleashed and Unfamiliar is a system-agnostic sourcebook for fantasy games. By rolling a few dice, a GM can create a unique canine companion for the adventuring group. This dog, wolf, jackal, or fox can serve as a familiar, guardian, companion, or as the result of a summoning spell.
The end result might look something like this:
Princess Ariadne is a Frost Hound, a blue-furred hunter from the North. Hatched from a large periwinkle egg inside a cave in the northlands. Slow, but powerful; doesn't inflict much damage, but can attack several times. Brave and stalwart, fights to the death. Cannot resist bread, and is easily bribed with rolls or baguettes. She can spit acid once per day; smacks her lips for several hours afterwards. Ariadne is only a fraction of the size that it will eventually attain; the day after the Feast of Red Souls, she will triple in size.