I've heard of write-in candidates, but never stand-ins... Candidate Admits Using Twin as Stand-In
Fri Apr 22, 2005 - Reuters

SAN ANTONIO, Texas (Reuters) - The leading candidate for mayor of San Antonio admitted on Thursday using his twin brother as a stand-in at a civic event without telling anyone it was not him.

Julian Castro, a 30-year-old city councilman, said brother Joaquin, his identical twin, rode for him in the annual River Parade through downtown San Antonio on Monday.  ¶ 6:04 PM