Mega Buster, known as the Rock Buster in Japan, is an ambidextrous arm cannon created by Dr. Light. It can fire three bullets of highly compressed solar energy at a time that, with the exception of the remake Mega Man Powered Up, can pass through walls. In Mega Man 4 onward, Mega Man can charge energy up to two degrees, firing charged shots. In Mega Man 9 and Mega Man 10, Mega Man can no longer charge his shot, suggesting that it has reverted to the original version.