David R. Megarry originally invented the classic TSR game Dungeon! in 1971. Remarkably, the board game is arguably an ancestor of Dungeons and Dragons, although he got his idea from Dungeons and Dragons co-creator Dave Arneson Blackmoor adventure map. His game idea was rejected by all of the established game publishers including Milton Bradley, Parker Brothers, Avalon Hill, and SPI until TSR bought it from him for 7.5% of their company stock after Dungeons and Dragons had already hit the market.