Makankōsappō (SPL BC)
A powerful beam attack created by Piccolo as a way to destroy his then arch-enemy Gokū. Piccolo first used the Makankōsappō in the battle against Raditz, killing both him and Gokū.
The move is performed by touching the index and middle fingers of one hand to the forehead and charging enough energy to attack. When ready the fingers are extended forward, the attacker shouts the name of the attack and a thin curly-cue like ray of energy is released. The resulting beam is quite powerful, drilling through most targets, and exploding on the one's it can't. The main disadvantage of the attack is the time required to build up enough energy for the focused burst.
Non-canon usage
Piccolo uses it additional times when battling Garlic Jr. and as a mental projection created inside Buu's mind. In the anime, Son Gohan uses a very similar move while practicing with Kuririn (in a mental battle) on the way to Namek. This move is also used by Cell several times, the Cell Juniors, and later by Buu after he absorbs Piccolo.
In the Dragon Ball movies, Piccolo uses this move in several of the movies he appears in.