Step 1: Learn Mouse Taxidermy
First, check out my Mouse Taxidermy Instructable. It covers all of the basic skills and tools you'll need to prepare your rat for its LED Throwiedom. Mice are smaller and easier to work with than rats, so I'd definitely recommend trying this with a mouse first.
There's no reason you can't make a Mouse LED Throwie; I just happened to have both a frozen rat and red LEDs of the proper size for rat eyes. I'll make some mouse LED throwies next, but it's really all the same thing. I'll put up pictures when I make the mice.
The rodents below are quick-thawing in lukewarm water; this is suboptimal and can be avoided through proper planning.
If you're ethically opposed to the concept of creative and/or decorative taxidermy (and have chosen to look anyway) I have two questions for you: do you wear leather, and do you eat meat? If you answered yes to either, can you/would you kill and prepare the animals necessary to procure this meat and leather? Willfully ignoring the source of your food and clothing hypocritically outsources the ethical questions and is ultimately disrespectful to the animals involved. If you're an ethical vegan and eschew leather, I respect your opinion and your desire to avoid viewing discomfiting images. Thus I carefully label the Intro page of these Instructables, hide the more graphic pictures on the later pages, and promise not to send you any taxidermy for Christmas.
Now back to your regularly scheduled Instructable.
Step 2: Make Voodoo Doll
Make a voodoo doll the same general size as your rodent.
Step 3: Wire Up Your LEDs
Solder the LEDs, switch, and battery together as shown below. Make sure to leave the wires long enough to traverse your rodent's body, and to cover any exposed metal bits (wire, battery, etc) with tape to avoid contact problems with your armature wires. I didn't remember to do this until a bit late, so it doesn't show up in the nicely staged pictures below.
Thanks to Eric for soldering these for me while I had my hands full of rat guts. Eric points out that you shouldn't solder directly to a battery, as it may explode and make a terrible mess. Instead you should really use a battery holder. We didn't want to waste the space and he was sure of his infallibility.
Step 4: Attach LED Assembly to Voodoo Doll
Exactly what you think it means.
I put the battery on the tail end, the switch over the heart, and the LEDs in rough position on the head then stitched the whole thing into place. That was fast and easy; just a few loose loops were enough to hold everything in place. You could wrap it in thread like you did the voodoo doll if that works well for you, though there's probably a loss of precision in placement.
Double-check that your LEDs work and that all metal parts are covered with electrical tape before moving on.
Step 5: Skin and Wire Your Rodent
Skin your rodent as described in the Mouse Taxidermy Instructable, leaving the arm and leg bones attached. Clean, wrap, and wire these bones in the same fashion; you may use the thicker wire if you're working with a big rat.
Note that rat connective tissue is stronger than that of a mouse, and their bones are bigger and heavier. It will probably take you a good bit longer to prepare your rat until you get used to these differences.
Step 6: Stuffing
After you've given the pelt a final clean-up, you're ready to go.
Insert the voodoo doll carefully; you've got lots of weird bits poking out all over, and you don't want them to catch. Work the LEDs out of the eye sockets, and wiggle them into proper position. I added a bit of cotton around the switch to soften its sharp corners, but it probably wasn't necessary.
Wire the arms, tail, and legs into place, but don't stitch up the back just yet.
Step 7: Add Magnets, Stitch, and Dry
Now we're going to add the magnets.
I put one magnet on either side of the ribcage, held on by electrical tape. My rat isn't likely to be thrown; instead she'll live on the front of my refrigerator, so I only need enough to keep her in place.
The weight of your rodent will determine the size/strength of magnet you need. TEST your magnets to make sure they'll hold tight enough; keep in mind that the magnet will be working thorugh a layer of electrical tape and rodent skin. Rats have much thicker skin than mice.
If you want to actually be able to throw your rodent and have it stick reliably, I'd advise more and stronger magnets in a variety of locations; just spread them around for maximum coverage. You could also make a magnet-laden outfit for your rodent, which would increase the effective power by omitting the insulating skin. Play around with it- this is the fun part!
My photographer wandered off, so I don't have any pictures of the magnet placement. I trust that you can determine this empirically.
Stitch your rat up, then sew or pin its mouth and feet and let it dry.
Step 8: Throw!
Throw, toss, or carefully stick your Throwie to a nice metal surface.
Since these critters require a fair amount of work, you'll probably want to retrieve your Mouse or Rat LED Throwie after use. Choose your site wisely and you can have nearly endless fun.
Let me know if you have any particularly good suggestions for Rodent Throwie deployment locations- pictures or video are even better!
Thanks to Eric for soldering; to Leslie, Eric, and Cloude for pictures; and to Ningo for the inspiration.