10 Video Game Sub-Bosses With Unexpected Second Phases
3. Red Eye - Sonic & Knuckles (1994)
The classic era of Sonic the Hedgehog games is famous for its high-speed gameplay, catchy soundtracks and often punishing difficulty. It's also known for its many, many boss fights, which appear at the end of each zone's three acts.
In the Death Egg Zone of Sonic & Knuckles, the Red Eye is fought as a sub-boss at the end of Act 1. A seemingly immobile robot turret, the Red Eye attacks with rotating metal spheres that move up and down the pillar in a kind of orbital pattern.
Each attack destroys one of the spheres, and after you do this eight times, the Red Eye pillar looks to be defeated. However...!
It's not. After the explosions disappear, the little eye module detaches from the pillar and is able to fly around on its own. Plates of spikes surround it, and if you're able to get past those and attack the eye, they'll spin around even faster for a short time.
Considering that it's hard enough already to hang onto your rings in Sonic & Knuckles, having a sub-boss pull out a second phase like this is definitely an unpleasant surprise.