Goku and Tien decide to go walk around and check out the city a little. As they are walking long, Goku notices a man that has been following them for awhile. Goku stops and turns around and says "Who are you and what do you want?"
The man says nothing, but only shows a blank evil foreboding face.
Goku thinks (something about this guy just doesn't seem right, I don't feel a power level) Tien steps up and says "hey Goku, don't worry, I got this guy, I can handle him"
Tien goes rushing towards him and as he's running at him, Goku senses something very bad about to happen and yells at Tien "NO! STOP! HE'S DIFFERENT!" as Goku gets ready to use instant transmission.
The man disappears and reappears right next to Goku in the blink of an eye. All of a sudden, Tien freezes and is sliced in half, but Goku doesn't falter and starts to use instant transmission. At the last second, the man grabs hold of Goku's arm and they both teleport.
They appear at Kami's lookout, but before Goku could even react, the man swings Goku around in the air with one hand and sends Goku flying through the lookout itself at blinding speed. Goku comes out the bottom side of the lookout and the entire lookout splits into 2.
Goku now knows there's no holding back. Just before an immense piece of the lookout smashes into Goku, he erupts with a monstrous roar creating an enormous aura that obliterates the falling piece of the lookout.
Goku had turned into Super Saiyan 3.
The man still standing where he first was, finally speaks, "This human...he's actually a super saiyan. Finally, at last, I found one, but this one seems different from the other saiyans."
Before the man can react, Goku teleports up to him and sends his knee grinding into his gut at full force, forcing him to cough up blood.
Without stopping, Goku follows up with a full force smack down, clenching both hands together in the air and raising them up in the air and bringing them crashing down onto the man's back, launching down through the clouds, crashing into the earth, making a large crater.
As the dust clears, you see him stand up and his eye pupils flash silver and his hair begins to spike up.
He says with menacing tone, "You are going to regret ever laying a hand on me."