Collars are not a very important part of the costume. Not all the cats even
have them. But if you do want a collar, there are several styles to choose
from. You might want a bowtie like what Mistoffelees has. You can get one
from your dad or maybe from a thrift store. You might be able to find a place
that sells spiked collars. You could also take a strip of leather and attatch
little jingle bells. Be sure to sew them on and glue them so they don’t jingle.
This is not a necessary part of the costume so don’t worry about it.