Red Sea Crossing (1983)

A Moses-themed Atari 2600 game that Steve Schustack wrote in 1983 and sold by mail order through a single magazine advertisement. Its existence went unrecorded until a copy turned up at a Cincinnati rummage sale in 2007, and doubters had a fair case until a 1983 Christianity Today advertisement surfaced in 2011 and confirmed the game was real. A second copy appeared in a Philadelphia shop in 2012, and only two have been verified. Red Sea Crossing is the clearest example here of a rarity being proven rather than simply asserted.