I'm a secret boss, stronger than the final boss but it requires specific actions to be taken in-game. I am myself, The Game Creator. I instantly break the fourth wall by explaining to the characters that I am their creator and they are my puppets.
Phase 1: My attacks consist of rapid punches and kicks.I jump around the level, so that there is only a small window of time for the characters to attack. My health bar is slightly shorter than that of the final boss.
Phase 2: I start to input cheat codes: god mode, extended health, increased power. My form changes to that of a digital demon. I launch blasts of data that follow the characters around, each doing a remarkable amount of damage. I am now much slower, but my constant volley of attacks keep the player from simply slashing out. My health bar is now longer than that of the final boss.
Phase 3: My apparent death. I explain to the characters that they do no longer belong to me, but to the player. I fade away...
But then the background warps to a silly picture of my face, with my hand being the only thing the characters can hit. I constantly warp the battlefield and change the appearance of the characters, putting them in silly outfits. My health bar is about 1.5 times longer now. When I'm at half of my health, I swipe away the health bar, hiding it in the menu, and giving subtle hints to its location. My death is very explosive.