Dragon Ball Z  volume 16 features story and art by Akira Toriyama.

Cell has fused with android #17, becoming the strongest being in the universe - but not for long! Training in the Room of Spirit and Time, where a year passes for every day outside, Vegeta and Trunks have gone beyond the Super Saiyan, reaching a level of power even greater than second-stage Cell!

Now, Cell is no match for Vegeta - but Vegeta hates a boring fight. Succumbing to his pride, he agrees to help Cell fuse with android #18, the last element Cell needs to become "perfect," so he can crush Cell at his maximum power! But Vegeta's battle-lust may spell the end of the world!