10 Hidden Video Game Bosses You Weren't Supposed To See

10. The Egg Janken - Sonic Mania

The Sonic games are absolutely jam-packed with secret and half-finished bosses, though perhaps the most interesting example of all occurs in Sonic Mania.

Shortly after the game hit stores and reversed the series' critical fortunes overnight, fans discovered an unused Robotnik/Eggman boss hidden within the data of the Studiopolis Zone.

Named the "Egg Janken," the boss is an egg-like mech piloted by Robotnik with two screens on it, on which the player and Robotnik to play a game of rock, paper, scissors.

Hitting the underside of the egg causes both screens to draw their hands - if Robotnik wins the player will suffer through a barrage of tricky attacks, while if the player wins Robotnik will incur damage. Such is the formula until one side is KO'd.

Unlike a lot of cut bosses still residing within a game's code, the Egg Janken is actually fully functional as a boss fight, and considering its conceptual cleverness it's surprising it ended up being left on the cutting room floor.