In the manga Dragon Ball, Goku’s signature energy attack is the Kamehameha.
The Kamehameha is a concentrated beam of energy taught to Goku by Master Roshi. Goku first uses it after seeing Roshi perform the technique, even though Roshi says it took him decades to master. The move became one of the defining visual symbols of Dragon Ball and its many later adaptations.
The attack is performed by gathering energy between the hands and releasing it forward as a powerful wave. Other characters, including Gohan, Krillin, and Master Roshi, also use versions of it, so it is not exclusive to Goku. However, Goku’s repeated use made the technique especially associated with him.
The name is often transliterated in several ways, including “Kamehameha” and “Kamehameha Wave.” It is unrelated to the historical Hawaiian king Kamehameha I; the Dragon Ball name was chosen as a playful reference by creator Akira Toriyama.