California could become the first state to legalize "magic mushrooms" if a ballot initiative becomes law.The measure would decriminalize the use of hallucinogenic mushrooms, which contain the psychedelic compound known as "psilocybin."Supporters would first need at least 365,000 signatures to get the measure on a statewide ballot.Kevin Saunders, who filed the measure, said it's a natural step after California's legalization of marijuana.