Teenage Mutant Ninja Turtles - Croc Attack! (Volume 12)
The Turtles discover that they're not alone in the sewer.  The green ooze which mutated them years ago also claimed another victim Leather Head!  Fueled by frustration, fear and blind rage, but tempered with intelligence, rationality and curiosity, will Leather Head turn out to be a valuable ally or a formidable foe?  And who is this mysterious friend he keeps talking about?