Super Mecha Sonic

Super Mecha Sonic is the final boss of Knuckles' story in Sonic & Knuckles, the echidna's last fight taking place in Sky Sanctuary Zone. After you have defeated Mecha Sonic in his normal form, the spiky blue robot jumps onto the Master Emerald, transforming into a faster, stronger, gold-er form.

Unlike Mecha Sonic, Super Mecha Sonic has the ability to fly. The main attack is 3 large energy balls that are fired from Super Mecha Sonic's chest. Super Mecha Sonic can also do a Spin attack while in the air, which is directed at Knuckles, charge down toward Knuckles, and occasionally fires out a circle of what look like chunkier rings - although these are damaging. Each time Super Mecha Sonic does the 3-sphere attack, it drains his power, and he will briefy revert to Mecha Sonic before recharging via the Master Emerald to transform again. It is only in these brief periods of normalcy that the boss is vulnerable to damage. When Mecha Sonic returns to its normal form, it can still defend itself by using a spin attack along the ground. Metal Sonic loses a bit of power after shooting every other circle or rings, causing him to become normal again and start to come back down, giving you a chance to hit - but be very quick, as Metal Sonic will return to Super form within a second (he won't even land).

8 hits destroys the robot entirely; rather than being left sparking but still-in-one-piece, as occurs when Sonic defeats him, Mecha Sonic explodes into itty-bitty pieces after Knuckles' final hit.

Unusual Transformation

Mecha Sonic's super-powered transformation is unusual from a continuity perspective for several reasons:

• The robot uses the Master Emerald to transform; the Chaos Emeralds are nowhere in sight. This means it is not a Super transformation in the traditional sense, and might even be considered to represent another class of power-up entirely (aside from Super / Hyper / Burning etc).
• No other character has ever been shown as able to power up from the Master Emerald (although there is some ambiguity regarding Super Ix in Sonic Chronicles: The Dark Brotherhood).
• No other robot has ever been shown as able to achieve a golden, glowy Super or Super-like transformation by any means. Gemerl's final boss form in Sonic Advance 3's Nonaggression is perhaps the closest analogue - a Chaos Emerald-powered metamorphosis into a souped-up mechanical behemoth. This, however, could possibly be considered a Perfect form, seeing how both Chaos and Dark Gaia became gigantic beasts in their Perfect forms.