Pro-Am 64 is the name of a cancelled game by Rare, intended to be part of the Pro-Am series. It was presented to Nintendo after which it was later reworked into Diddy Kong Racing.
The game was originally a real-time strategy game themed on cavemen and time travelling. Eventually it became a racing game instead called Wild Cartoon Kingdom, based on a theme park and attractions. After this, it became Adventure Racers; intended as a sequel to the game R.C. Pro Am on NES and then finally named Pro-Am 64.
Pro-Am 64 originally featured a different main character before Shigeru Miyamoto suggested to change it, so Rare decided Diddy Kong. This character was known as Timber the Tiger, who would appear in Diddy Kong Racing, but not as the main character.