As sort of a companion to my post on the guises of various spirits, I figured I'd open up a subject where everyone can describe what sorts of familiars their magically active characters or NPCs have had, any cool ideas that you wish you could implement some-day, and any cool but crazy ideas for ally spirits that you'd never implement because your friends would smack you upside the head (both in game and out of game).
1. A white, fluffy and slightly obese house cat known as "Mr. Bigglesworth" who speaks with a disturbingly low voice and often attempts to push his master towards world domination. Has an irrational fear of midgets and dwarves.
2. A wispy reflection of one highly stereotyped facet of your personality such as "My self-doubt", "My slowly building homicidal urges", "My desire for a family", or "My latent bisexuality". Perhaps the ally actually occasionally puts forward the possibility that you're the ally spirit and it's really you.
3. A small mouse-like creature with the Elemental Aura (Electricity), and Blast (electricity) powers. Due to a flaw in the ally summoning formula, it can only repeat it's own name over and over again.
4. An imp who likes nothing more than to confuse acquaintances with a barrage of legal jargon. And who insists on getting any contracts regarding any run it's master goes on signed in triplicate. Needless to say, designing this critter means giving it a specialty in Legalese and a Con specialty in "Irrelevant legal information".
5. The supposed future self of the magician in question, who often sighs when the magician screws up as if he knew it would happen and then when asked why he didn't warn the magician that the action would fail says "You don't want to be stuck in a stable time loop, do you?". It's not all bad though-the divination power that the creature possesses works wonders...now if only you could figure out why he keeps on talking about the biggest city of his time...a metropolis of 5,000 people.
6. A spider like creature seemingly made from discarded needles whose fangs drip opiate venom. Has a jolly disposition, considering that it's your incarnated former addiction to heroin-you guys go way back and used to be the best of friends.
I'd love to see some more ideas-a mix of the silly and the serious, the funny and the freaky-plus any that you've seen in actual play that struck your fancy.