If the game is beaten with 100% completion (all the Jiggies found), Mumbo Jumbo would show the player three moving pictures revealing inaccessible areas (the door in the alcove of Gobi's Valley, a raised Sharkfood Island in Treasure Trove Cove, and the ice wall in Wozza's cave in Freezeezy Peak). The pictures showed Banjo and Kazooie collecting the Blue and Pink Eggs and an Ice Key and Mumbo mentions that the secret items would be used in the next game, making the first mention of the sequel Banjo-Tooie. However, if the player went back to these areas after the credits, they would still find the areas inaccessible, although you could view the Ice Key during gameplay.
Originally, these eggs and the Ice Key were to be used in Banjo-Tooie to unlock exclusive material. This would involve a technique called hot swapping, where the player would turn their system on with Banjo-Kazooie playing, then swap it to the Tooie cartridge within a 10 second time limit. Revisions to the N64 would have given the player 1 second to swap the cartridges, making it virtually impossible. Plus, it could potientially damage your system, so the idea was scrapped.
Two hackers, Alan "IceMario" Pierce and Mitchell "SubDrag" Kleiman of the fansite, "Rare Witch Project" discovered in-game cheats that would allow you to access these previously inaccessible areas. Once collected, they would appear one screen after Click Clock Wood in the View Totals menu in an area called "Stop 'N' Swop". However, there were no use for these items and once collected, they could not be erased and they would appear on all your game files.
In Banjo-Tooie, the Yellow, Blue and Pink Eggs (as well as the Ice Key) were included in the game to unlock bonuses when hatched by Heggy and Kazooie after learning Kazooie's Hatch move in Terrydactyland. The Blue and Pink eggs were found by breaking hidden Banjo-Kazooie game cartridges found in Spiral Mountain, and the Ice Key was found by using the Grip Grab move in Jinjo Village to reach an alcove. The Yellow Egg was already able to be accessed in Heggy's house.
- Yellow Egg: Unlocks Jinjo as a player in multiplayer.
- Blue Egg: Unlocks the "Homing Eggs" cheat
- Pink Egg: Unlocks the "Breegull Bash" move
- Ice Key: Unlocks a safe found in Hailfire Peaks to collect the rare Mega-Glowbo (the player has to use the Talon Torpedo in Glitter Gulch Mine to break a rock, so they can swim through an underwater tunnel to reach the safe). Giving this to Humba Wumba in her wigwam found in Pine Grove will unlock the Dragon Kazooie transformation.
Here are the cheat codes to unlock the Eggs and Ice Key in Banjo-Kazooie. To enter them, head into the sandcastle in Treasure Trove Cove. You must enter the word "Cheat" in before each cheat code.
- Ice Key (Wozza's Cave - Freezeezy Peak): CHEAT NOW YOU CAN SEE A NICE ICE KEY WHICH YOU CAN HAVE FOR FREE
- Pink Egg (Sharkfood Island - Treasure Trove Cove) : CHEAT OUT OF THE SEA IT RISES TO REVEAL MORE SECRET PRIZES
- Blue Egg (Alcove Door - Gobi's Valley): CHEAT A DESERT DOOR OPENS WIDE ANCIENT SECRETS WAIT INSIDE
- Cyan Egg (Blocked Cellar - Mad Monster Mansion): CHEAT DONT YOU GO AND TELL HER ABOUT THE SECRET IN HER CELLAR
- Green Egg (Above Loggo in the Bathroom - Mad Monster Mansion): CHEAT AMIDST THE HAUNTED GLOOM A SECRET IN THE BATHROOM
- Red Egg (On a bed in Captain's Cabin - Rusty Bucket Bay): CHEAT THIS SECRET YOULL BE GRABBIN IN THE CAPTAINS CABIN
- Yellow Egg (On Nabnut's Table in Winter - Click Clock Wood): CHEAT NOW BANJO WILL BE ABLE TO SEE IT ON NABNUTS TABLE
- It was ranked #11 in YouTube user Tats TopsVideos' "Top 35 Hoaxes in Games." (it was credited just as The Ice Key, but made mentions of SnS and the eggs as well)