The Pink Mystery Egg was one six secret eggs found in Banjo-Kazooie. When you typed in a cheat code, the Sharkfood Island in Treasure Trove Cove would be raised from the ground for you to enter. Then, after a long jumping segment, the pink egg is yours. Mumbo Jumbo would show you the pink egg in a picture if you collected all 100 Jiggies after defeating Grunty.