Metal Guardian looks like a giant metallic ball initially, but it reveals an eye and hands when it is disturbed. Metal Guardian's armored exterior is a highly reflective copper or bronze, while its "core" appears to consist of steel or iron. Its design may be vaguely based on Laser Ball considering they both give the same Copy Ability, but its core slightly resembles that of a Wheelie.
Metal Guardian remains secluded and encased in its armor until Kirby approaches it. When encountered, the machine floats in a figure eight and shoot lasers at Kirby. It can shoot a charged laser or three regular lasers in three directions.