From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Piccolo puts his hands together and charges a blazing white aura to form a yellow sphere of energy in his hands. He then brings his hands forward and fires the energy sphere, inflicting a massive amount of damage.
Dragon Ball Z
Piccolo used this attack in his battle against Imperfect Cell. After being knocked down by Imperfect Cell, Piccolo charged up and fired the Makousen at the approaching Imperfect Cell, creating a huge explosion. While it did blast Imperfect Cell into the ocean, the Artificial Human emerged completely unscathed much to Piccolo's shock.
It later appeared in Dragon Ball: Raging Blast and is Piccolo's Ultimate Attack. When someone is hit by this attack in this game, it changes from an energy wave to a large energy sphere as in the original series. This also occurs in Dragon Ball: Raging Blast 2, where the attack has been upgraded and is nicer looking, and Dragon Ball Z: Ultimate Tenkaichi, where it has been further upgraded.