The Shredder and his mystics are effortlessly beaten by the Turtles' dragon forms.
Getting Crap Past the Radar: The Tengu Shredder begins to consider keeping Karai as a slave after stripping her down to her very form-fitting underwear.
No, You: Karai's not very good at trash-talking. She does this several times to the Tengu Shredder.
Shapeshifter Guilt Trip: While not exactly a shapeshifter, the Demon Shredder fulfills the spirit of the trope when he uses his human face, the same as Karai's adoptive father's one, to take her off guard at the very moment when she seemed to have an advantage, though he later states that he was just playing with her the whole time.