He goes there to show off his son Gohan named after his adopted grandfather.

Soon after he arrives his blood brother Raditz from the planet Vegeta zooms down from the sky.

Raditz beats up Goku because he refuses to help Raditz destroy the planet. But sooner or later Goku graspes Raditzes tail which is a natural weakness for saiyans while Piccolo charges his special beam cannon.

When Piccolo gets done he kills both goku and Raditz.