The humble Hadouken is also referred to as the "fireball". The basic special move of the Street Fighter series first made popular in the late 80s-early 90s, this blue flame projectile originally sported a ghostly face. It was first utilized by Ryu and Ken, and later made its way to other fighters in varying forms such as Chun Li, Guy, Akuma and others.

Many people born around the years 1982-86 will duck if the word "HADOUKEN!" (/me ducks) is shouted in their vicinity. Or maybe that's just me.