The Sunken Temple of the Amphibian God

From itch.io: An ancient sunken temple at the bottom of a lake, a haunting cult and a sleeping god softly whispering. The Sunken Temple of the Amphibian God is a system-neutral dungeon designed to be played with any fantasy, OSR, or FKR game. Contents: Crazed cultists, frog-men, giant eels, hallucinogenic powders, ancient nobles, and an orb to ponder.