Carltron's Robot jumps back and forth along the top of the room, firing a rapid barrage of rockets straight down when it lands. Explosions burst around it regularly, dealing heavy damage to the player if they get too close. Carltron's Robot is almost immune to alchemy with 60 alchemy defense, so the player must use physical blows.
If the player has Barrier and a charged weapon, the battle is very simple. Provided the player does not move, Carltron's Robot will not, either. Thus the player can use Barrier to become immune to damage, and simply attack the robot over and over with impunity, the robot making no effort to defend itself or dodge the blows. The Neutron Blade is particularly effective for this, able to deal multiple hits with its Level 3 attack. Energize helps speed this up.
Without Barrier, the player should keep their distance and use the Laser Lance or the Bazooka. Time attacks to strike as Carltron's robot is landing from a jump to move into attack position, and then quickly dodge its counterattack.
If the player is quick, they can run up the sides of the arena to platforms behind Carltron's Robot. Here, the robot will be entirely unable to harm them, letting the player attack without fear until the robot falls.
The player gets 100,000 experience from this fight, which is irrelevant since there is no further gameplay past this point.