Wikipedia
B-Daman
is a marble shooting toy produced in Japan by Takara.
The blaster's design is a humanoid figure at the centre, from which a specially made marble, is launched (but even other marbles of the same size may be used). Different attachments are used to change a B-Daman's accuracy, power, balance, control, and rapid fire. They are customizable and each have a special gimmick.
In the English language Battle B-Daman toys, the marbles are referred to as "B-Dama". In all cases they are simply called "marbles" (; biidama, hence the name "B-Daman") in Japan.