You will use the Robot Crab to open the metal hatch that is glowing red-hot. If you try to click it, you’ll see it’s much too hot to touch. Sprocket will break the Robot Crap and it will cool the hot surface.
How to get Robot Crab
Pass by Sully’s shop and go to the blue building in the middle. This is the living quarters. Jump up the platforms on the left side and then run past the door. You’ll see a robot crab here. Jump up and land on top of him to make him bounce and flip over. When he does, you can pick the robot crab.