The Crystal Egg Zone boss is an optional boss battle in the Master System and Game Gear game Sonic the Hedgehog 2. The mechanical arena is the seventh and final Master Robot, operated by Dr. Robotnik in a last effort to eradicate Sonic.
Sonic manages to track Dr. Robotnik down and battles him in his new contraption. The hedgehog manages to defeat the doctor, resulting in the latter running from him and teleporting away. Sonic is upset that Robotnik managed to escape, but is soon reunited with Tails, who is teleported to the location in the doctor's place, freed from his grasp.
The battle takes place inside a lightning chamber, which Dr. Robotnik makes extra-fatal by throwing gyrating, flower-shaped energy bolts into the mix. However, the boss actually is not that difficult if Sonic stays inside the transport chutes until the chamber clears, at which point he can leap out, attack Robotnik and dive back in to safety before the attacks renew themselves.
|Master System||Masafumi Ogata, Naofumi Hataya, Tomonori Sawada||1:40|
|Game Gear||Masafumi Ogata, Naofumi Hataya, Tomonori Sawada||2:03|
- This is the first instance of a "True Final Boss" in the series.