In the first episode, Splinter explained that the mutagen turns animals/people into whatever creature they touched last. But in this episode, when Rocksteady flings a worm into the mutagen pool, it has the head of a rhino, but also grows wings and arms that are unlike his.
Donatello: What a shame. I must have reversed those two wires.
Shredder: (quietly angry) You double-crossed me!!
Donatello: One double-cross deserves another!
Rocksteady and Bebop do not wear their regular clothes in this episode.
Episode included on the Teenage Mutant Ninja Turtles Season 5 DVD release.
In this episode Shredder is voiced by Jim Cummings.
(Response to note about the missiles) Donatello mentions that later in the episode when the plan backfires on Shredder who just seemed to have forgotten about the fact that they are cold-blooded.
Shredder talks about using heat seeking missiles against the Turtles, but they are cold-blooded. Donatello confirmed this earlier in the series, when a similar tactic was tried against them.