A Bitcoin doubler, come on m8. The only way it gets doubled is if people (like you, presumably) act impotent and force businesses and people to keep using the chain that was forked away. If every exchange, every service, every business switches to the new chain then nothing would get doubled and we could go on our merry ways without having any issues like the one you're describing.

However we all know that people will be belligerent and we're just going to have to wait for everyone to give up trying to exploit the old chain.