In Dragonball Z, when Gohan changed into an Ozoro, Piccolo found an appropriate solution, destroy the moon. Easy-peasy.

The real question is, when Goku used his Genki Dama (on two occations, by the way), it never resulted in anything more than a relatively small crater. With all the power stored inside that sphere (easy above a billion, and over 9000), shouldn't it have caused a bit more damage? Piccolo managed to destroy the moon, easily, with power level of less than 1000.

In Dragonball Z, when Gohan changed into an Ozoro, Piccolo found an appropriate solution, destroy the moon. Easy-peasy.

The real question is, when Goku used his Genki Dama (on two occasions, by the way), it never resulted in anything more than a relatively small crater. With all the power stored inside that sphere (easy above a billion, and over 9000), shouldn't it have caused a bit more damage? Piccolo managed to destroy the moon, easily, with power level of less than 1000.