Frieza
Similar to the normal Kienzan (most commonly used by Krillin), Frieza's are faster, a different color (purple), and can be controlled remotely. Frieza creates two of these to hound Goku until he's sliced in half by his own attack. Called the Energy Disc or "Destructo Disc" in the English version. Dragon Ball Z: Budokai Tenkaichi 2 names this attack the "Death Saucer."