The Bouncy Boss Robot (ホッピング・エッグバルカン Hoppingu Eggubarukan?, lit. "Hopping EggVulcan" or "Hopping EggVolkan") is the Master Robot of Sleeping Egg Zone in Sonic Chaos. It is a bouncing, armed mobile with a robotic head of Dr. Robotnik, and is the third boss of the game.
The battle takes place in a wide arena at the end of Sleeping Egg Zone Act 3. Upon approaching it, the Bouncy Boss Robot descends slowly to the ground and quickly starts its pattern. It starts firing three fast moving projectiles from machine guns at a time, while also bouncing in the air by using its large spring. The Bouncy Boss Robot starts moving to the left and then at the mid-point, it backs down and repeats the pattern.
Although the machine's movement is simple, the major problem comes from its rapid-fire machine guns, which can be hard to avoid. The player must also take great care not to get crushed under the spring and carefully time attacks while dodging projectiles. After eight hits on Master System or five hits on Game Gear, the Bouncy Boss Robot is destroyed and the player moves to the next Zone.
- The Bouncy Boss Robot was originally unnamed in the Master System manual; however, in a Sonic The Comic Q Zone that covered it, it was alternatively dubbed The Pogo-Powered Robotnik!
- If the player Spin Dashes underneath the Bouncy Boss Robot's spring at right time, the playable character's death animation goes down faster due being crushed.
- Egg Press from Sonic Advance is extremely similar to the Bouncy Boss Robot with the exception for having no machine guns and performing different attack patterns.