This is an idea to allow players to make golem pets by creating a body using the existing pottery system, and giving it life via a chem (scroll containing holy life-giving writ) produced by a player priest.
Adding new items to the list of things which can be made on a pottery wheel isn't too hard. To keep things simple, I think it would be easiest if animal bodies could be made in the same way as any other items - no special steps or requirements. The skill-checks to create animal bodies would be very high however, since such designs would be much harder to make than something like a bowl.
It would be nice if different degrees of success resulted in different looking animals, in slightly more than a "fill in the adjective" way. Both the short and long descs could change, with nicely written descriptions for each level of success - remember, this is what people will be looking at. Perhaps there could be a minimum level of success required for the chem to work - i.e. if you make a vague animal shaped lump, it wouldn't come to life when you put a chem into it.
I can't see a problem with allowing animal bodies to be decorated like other pottery - patterns may look a bit odd (but if that's your thing, go nuts), but glazing is simple enough and lets you choose the colour of your pet.
Creating a chem would be a priest only ability, with quite high skill requirements. It would require a piece of paper, and possibly a writing implement - although I can see the writing burning itself onto the scroll magica-erm, divinely. The primary skill used would be fa.it.scroll, but others could be used in addition - e.g. fa.ri.special or fa.ri.mi.target.
It also makes sense to also require a suitable clay animal body in which to place the chem, since creating chems willy nilly without purpose seems a bit out of theme. This leads into the question of ownership - who does the finished product belong to? In the end, here's what I feel would be logical requirements for chem creation - feel free to disagree and implement differently:
The syntax for the chem creation would be somewhat complex, but nothing too scary:
create chem for <vessel> named <pet name> using <paper> for <owner>
Before any faithing is done, the owner (if not the priest) is prompted to accept ownership of the creature - which they must confirm in order to continue. Then, the faith skills are put to use and if all goes well, the chem is placed inside the animal and it comes to life. Failures could involve anything from the scroll bursting into flames, to the priest being temporarily possessed by an animal persona, to the body exploding...
I'm not sure how to handle removing the chem - pet ceases to be alive, and can be brought back by replacing the chem? What if another chem is placed inside it? What if the chem is placed inside another body? With what I wrote earlier about creating chems without purpose, linking a chem to a body seems to make sense, but I'm not sure how correct that is with DW canon or how much extra coding effort it would take. I don't see a problem with removing a chem and replacing it with another one (through the proper procedure), though...
If a player wishes to transfer ownership of a pet they could also possibly have a priest perform a special command/ritual for the purpose - requiring the current and future owners to both be present and confirm it. Lower skill-checks than needed to create a new chem, etc. Killing a pet could be a simple matter of the owner removing the chem and disposing of the body.
If the body is to act as a container, then I think the same rules that apply to fruitbats and clouds would be good to limit the ability for some bugger to pinch your pet's brain.
So you've made a golem pet, now what? Well... not much. Golems don't tend to be spammy, so the few chats they would have would be for things such as not scratching itself, not nuzzling your crotch... They just stand there.