Curryma is a forbidden spice and reacts to the hidden darkness, desire and impurities in people's heart. Once affected, they become black as a result of black magic. It is obviously a spice developed by dark magic users such as the Indians but ironically it was spiked by the white man. The man must've been tainted by the indian's black magic and turned evil. In episode 15, Harold West tries to calm down Meena, who is affected by curryma. Curryma is added to the curry and poison curry is formed!