The Catwoman from Channel Six - S2-E12
Continuity mistake: When Leonardo cuts off April's collar, she asks what happened, but instead of it being Leonardo standing there with the sword, it's Donatello with the sword.
Continuity mistake: At the end, when Teddy and his friends get the directions to the Wizard's fortress, Prince Arin's hair is bright yellow as he shakes Wooly's hand. In the next shot it's back to his normal orange hair.