Humans can't transform at least not without a lot of negative side effects, The spell is probably fake, honestly I want to know who would create a fake spell that required eating raw meat and a dead animal, only let her try it if she ultimately will not listen to reason, and maybe not even then because no matter what raw meat can wreck your body, honestly no offense to your friend but if I feel she may need help.
Mossgoth, if she does the spell, she may think it worked and that she now has a dragon spirit. I've met people like your friend before. They play into their desires and make the unreal real to them. I think you are right to drop it, but if she keeps it up, you may want to be with her to make sure she doesn't do anything really dangerous, like eat road kill or something. Best of luck to both of you :)
Your bio says you are 14, so it is likely your friend is a similar age and experiencing the last of childhood fantasy and imagination. It is up to you to decide if you want to continue playing make believe or if you want to go forward with maturity.