In Roman mythology, Mefitis was a goddess of Italic origins primarily worshipped by the Samnites and Osci in southern Italy. Mefitis was associated with water— particularly foul-smelling or sulfurous water— and noxious fumes. Her main temple was situated near Lake Ampsanctus, which was described as deadly by Cicero and Pliny. The temple itself was reported to contain poisonous gas that killed anyone who entered, and Virgil described it as an entrance to the underworld.