Teen Titans, Vol. 3 #15 (2004)

Beast Boys and Girls, Part Three: Changelings
Cyborg bursts in before Dr. Register can dissect the cured Garfield Logan. Now "Zookeeper", Register dives from the window, transforming. He has the same powers Garfield used to have, save that the animals he becomes are purple. Zookeeper fights Cyborg, Starfire and Wondergirl and finally Gar grabs a hypo full of sakutia and injects himself. This restores his powers, which he uses to battle Zookeeper. Finally, Beast Boy becomes a funnel web spider and paralyzes Zookeeper. Cassie learns from Ares that a turning point is coming in her life, and that she must prepare. She also meets Raven, who wants... to go to school, and needs help choosing clothing. In Smallville, Superboy gets a call from Tim Drake. Robin is back!
Release Date: 2004