Sunny Side Up -
Defeated Death Egg Robot.
In the first phase, let him lock onto you and then move quickly away from the target. His fist will hit the ground. He'll do a quick kick with one of his feet and then he'll hover to change direction. Run under him when he does this and then hit him in his glowing green underside. Do this twice.
The second phase is a bit harder as you have to hit the switches to activate the bombs and then have him lock onto you while you're standing near the bombs so that he punches them. But you have to be far enough away so that you don't hit the bomb, and if its not done right, he'll destroy too much platform around the bomb and you won't be able to run up to his arm to attack him after he's stunned. I found the best place to do it was on the far left area where both the switch and the bomb were on an equal level with each other, as opposed to the other three where you had to activate a lower switch and then jump up a level to get him to lock on. Do this twice for the achievement.