Question for the flist

So, I have me a new story idea. (Well, technically I've been wracking my brains to come up with a dragon  short story idea for awhile because of a submissions call I saw somewhere and I've finally thought of something).

My question is: How many Barbie sacrifices would it take to make a stuffed dragon manifest into a real dragon? Or could the stuffed dragon just eat the Barbie that is most beloved of teh main character? Would that be best?