When R2DA reaches a certain birthday, a new boss appears.
It would be a giant cake that would use cameo attacks reskinned from bosses.
Example: From Yeti 1, it would throw a giant frosting ball.
From Yeti 2, it would rain sharp frosting.
From Crab 2, a smash creating a small frosting wall.
From, Pumpkinator, candles fly out of it's head to blow up an area.
From King Cherrycake, summons Birthday Cakes and a Frosting Cloud to obliterate.
It's own personal skill would make it fire a giant ball of confetti. It has insane knock back but can only do 5 damage at max.