Radcliffe stars as Ignatius "Ig" Perrish, who finds himself accused of the rape and murder of his beloved girlfriend. He wakes up to find he’s suddenly sprouted horns, which somehow give him the power to compel people to reveal their darkest secrets. He decides to use the power to find the real killer, all while being demonized by the local townsfolk.
Radcliffe, who was promoting the film at SDCC, managed to elude the press and mingle with the masses by donning a Spider-Man costume to walk the floor over the weekend. It was probably easier than using a Polyjuice Potion.