They have a very small metal body, with a pipe on each corner. A pink spot can be seen in the middle, this possibly being their eye.
Exploding robots are placed often near other exploding robots. When the Hazmat Hero goes near an exploding robot, the robot will begin to flash red. Soon, it will explode damaging the player if the Hazmat Hero is close enough. The explosion of the exploding robot is a little bit smaller than that of an explosion from the player's bomb.