A doctored coin saw the face of Spain's King Juan Carlos replaced by cartoon character Homer Simpson. Spanish Sweetshop owner Jose Martinez was stunned when he found the euro among his day's takings while cashing up his till. Jose said he has recently started taking an interest in coins after finding three euros from Malta, but admits nothing prepared him for the shock of seeing ?The Simpsons' character's face in place of the monarch's profile. Jose, of Aviles, said: "The coin must have been done by a professional. It's an impressive piece of work." The other side of the coin - which displays a map of Europe - had not been altered, sparking rumours that the defacement, which is a criminal offence, was part of a republican conspiracy against the Spanish monarchy. Because of the high quality of the coin, there has been much speculation that it is not the only one in existence. The shop-keeper - who carries the coin everywhere with him - has been inundated with bids from ?The Simpsons' fans worldwide, but Jose insists he doesn't want to part with it.