Instructions
Begin the boss fight with the Egg Beetle. You'll be running along a long, narrow walkway as the Egg Beetle moves away from you. Run through the rings to fill up your "Boost" gauge. Avoid the cubes that the Egg Beetle throws at you by pressing either "L1" to do a "Quick Step" move to the left or "R1" to do a "Quick Step" move to the right. Keep doing this until the Egg Beetle slows down for a pincer attack.
Press the "Square" button to perform a "Sonic Boost" attack to damage the Egg Beetle. It will repeat its previous method of running away while hurling cubes at you. Avoid the cubes and use the "Sonic Boost" to hurt it when it slows down for a pincer attack again. The Egg Beetle will fly up into the air and change its attack strategy.
Dodge the missiles that come at you from the left side of the screen. Press "X" to jump just before the bottom missile reaches your location to avoid the missiles. The Egg Beetle will then try to pinch you from the side, so jump out of the way to avoid taking damage. It will eventually go back in front of you to try a frontal pincer attack.
Press "Square" to do another "Sonic Boost" attack. It will start throwing cubes again, so avoid the cubes and use "Sonic Boost" to attack the Egg Beetle whenever it slows down to attempt a pincer attack. Keep doing this until the Egg Beetle starts flying along the side of the walkway again and throwing missiles at you. Jump to avoid the missiles and the pincer attack from the side. Keep doing this until the Egg Beetle goes back to the walkway in front of you.
Press "Square" to do one more "Sonic Burst" attack when the Egg Beetle tries another frontal pincer attack. This will defeat the Egg Beetle and end the boss battle.