A myth made up by a hater.
The story goes that Wyatt Earp and “Mysterious” Dave Mather were in Mobeetie, Texas in 1878. Reportedly, the pair ran a con game, selling fake gold bricks to unsuspecting citizens of the area. But there’s a problem—contemporary newspapers had no such accounts. And the author who alleged the scam in 1963, Ed Bartholomew, was no fan of the Earp clan. For whatever the reason, Bartholomew apparently concocted the story—and some other publications passed it on as truth.