In what episode of does Goku turn Super Saiyan for the first time?
After Frieza got hit by the spirit Bomb, it seemed to Gohan that his father was caught in the blast with Frieza. Hopfully looking out for any movement or life, Gohan finally catches glimpse of piccolo and his father pulling themselves to land from the watery deep they fell into. Feeling they had won, Goku, Piccolo, Gohan and Krillin expressed relief and even had a laugh. While on King Kai’s Plant, King Kai relays the good news to the Z fighters which included Yamcha, Tien Shinhan and Chiaotzu who were at the time fighting the Ginyu Force there. Back on Namek Goku, Piccolo, Krillin and Gohan prepares to leave to find Bulma.
However things took an ugly turn in the middle of a conversation between Krillin and Piccolo as Krillin starts to shake while looking over at a nearby cliff. When the other Z fighters turned to look they saw Frieza standing on the cliff with damages to his body, however still able to fight; He was able to fire his death bean which hit piccolo. Goku then tells Gohan and Krillin to take piccolo, find Bulma and Escape to Earth.
In a retaliation attempt, Frieza lunches Krillin into the air and detonates his energy inside of Krillin blowing him up. Goku, angered by the death of Krillin, rage began to grow so much so that he starts to undergoes a strange transformation of yellow hair, green eyes and yellow aura surrounding him. This is where Goku turns Super Sayan for the first time.