Zzub, Feara, Blister and X Treme are evil clones of Team Lightyear, created by Evil Emperor Zurg. They are children, because Zurg was too impatient to keep them in the cloning chambers until they were fully grown, and they escaped him before he could put them back in. They were in the episode Clone Rangers. At the end of the episode, Zurg created another set of clones of Zzub, Feara and Blister, although this time, he left them in the cloning chamber too long, and got geriatric versions of them.