If the character your making has a collar, this is probably the easiest part of your costume. There are many ways to
get or make a collar.
1) You could buy a spiked collar from your local pet store. They usually sell spiked dog collars.
Also they sell other types of dog collars and cat collars to pick from. There's a picture at the bottom showing an example.
2) You know those 'punk' braclets some people wear? They have like spikes or studs on them? If you buy two that are the
same, you can click them together to make a sudded/spiked collar. There's a picture at the bottom showing an example.
3) If you want to make a soft collar, you can use yarn and braid it and add a nice little tinkley
bell. I've done that for a Skimbleshanks collar. Shown at the bottom of the page. Just make sure the collar is big enough
to fit around your neck and is able to be tied. Or you can add a little clip.
5) You can order one off
ebay. They've got quite a bit of spiked collars.