4x22 - Dragon Ball Z: Dragon Box

The three Artificial Humans, No. 16, No. 17, and No. 18, arrive at the Kame House in search of Goku. However, Goku is, of course, not there, being engaged in training at Kami's temple. Piccolo, having powered up by merging with Kami, lures the Artificial Humans away and begins fighting No. 17 on an uninhabited island. The tremendous power released by Piccolo as he fought No. 17 is detected by Cell, who is searching for the Artificial Humans...!!