A Mad Bumper is meant to resemble a cartoonized version of real-world cars. Its body is primarily red, and its roof is black with orange flames and a bent, black antenna on its top. Its four black tires are set rather close together and have purple hubcaps, and its fenders are silver. The white grill of the car acts as the Heartless's sharp-toothed mouth. It also has two headlights with yellow tips that act as its "eyes", though it has actual, glowing yellow eyes set in its black windshield. Its Heartless emblem is actually its hood ornament.
The Mad Bumper's name references its berserk, erratic rages when it is low on health. A bumper is a part of an automobile designed to help it withstand the impact of a collision.
Unlike the Hot Rod, the Mad Bumper executes all its moves at a much faster pace, attacking more relentlessly than ever. When half of its HP bar is depleted, a purple aura will appear around it. When this happens, watch out! It will rev up and rush towards you, and if you're in the way, it will send you flying. It does this rush attack thrice, and pauses for a while before it begins rushing towards you once again.
In all cases, when it attacks you, immediately Guard. When the Mad Bumper rushes at you, a well-timed Guard or High Jump can save you from being sent flying. When it pauses, it is open for an attack, so finish it off.
Alternatively, if you're the type to use magic, use Reflega, and make sure that the edges of that spell hit the Mad Bumper - but, time it well.