Banjo Kazooie (Stop 'n' Swop)

[PossumCheckers]

Rare, makers of Banjo Kazooie planned on implementing a mechanism that somehow linked both Banjo Kazooie and Banjo Tooie, known as Stop n Swop. It was believed doing so would unlock special items or secrets in the game. However, Nintendo was not on board with the idea and it was removed abruptly. Evidence of this still exists within the game, by claiming items such as the ice key and strange colored eggs that seem to have no purpose.