Rear Egg
Rear Egg is Banjo & Kazooie's down special move. It involves Banjo crouching down while Kazooie deploys a Grenade Egg backwards, an explosive item. The egg bounces in a slightly unpredictable fashion before detonating on contact or on a timer. As an item, it can be picked up by any player, though this does not stop it from exploding in characters' hands.
Origin
Banjo-Tooie introduces different types of eggs aside from the standard Blue Eggs; Grenade Eggs are the third egg type. They explode instead of simply breaking on impact or distance expiry, dealing high damage and destroying many sorts of objects, but also hurt Kazooie if they explode too close. Kazooie can carry only 25 of them (though Cheato can double this limit). Grenade Eggs can only be fired one at a time and are mandatory for defeating several enemies and bosses. In the multiplayer first-person shooter mode, Grenade Eggs deal 4 damage (out of most characters' 8 health) and can cause friendly fire.