Lamentations of the Flame Princess (LotFP) is an Old School Renaissance (OSR) horror RPG created by James Edward Raggi IV, who has run LotFP since 2009. Its rules emulate 1970s–80s Dungeons & Dragons as closely as the OGL allows.
It works in weird fiction spanning cosmic horror, grindhouse sensibilities, and experimental formats, and is notorious for deliberately uncomfortable, transgressive body-horror content.
By placing world-ending horrors within reach from low levels, all inside the familiar frame of Basic D&D rules, it has been widely influential on the OSR movement and indie horror designers.