Butt Biter: Buttercup in her dog form. She defeats Mojo this way.
Killed Mid-Sentence: A non-fatal example; The Mayor, who is already half dog completes his transformation just as he's about to say Mojo's name. Same with the first talking dog the girls run in to, who begs for help before being reduced to barks.
Laser-Guided Karma: Mojo gets a little too cocky and thus is easy prey for Buttercup when she bites him in the butt, causing him to break the Anubis Dog Head; the resulting shockwave restores everyone to normal and leaves him as a mutt. Bonus points for being the effect of an actual laser.
Literal-Minded: As a dog, Professor Utonium can only say "Bow Wow Wow Wow" when reciting Mojo's name. Bubbles misinterprets this as the villain's real name until Blossom realizes what he actually meant to say.
Morphic Resonance: When the citizens turn into dogs, they retain some of their traits when they were human. For example, the girls' fur is the same as their hair colors and they retain their faces, while the Professor's fur is the same white as his coat.
Didn't Think This Through: Sedusa didn't take any precautions to prevent the Mayor from calling the Powerpuff Girls for help, and instead of making off with her prize she returns to the Girls' house with her stash of jewels. By then, the Girls had already put all the pieces together.
Earn Your Happy Ending: When Professor decides to tell girls to call the police to arrest Sedusa. And Professor tells the girls Sedusa will not deceive him anymore.
Here We Go Again!: Said by the Narrator at the end where another woman shows up and baked a pie for the Professor and the girls when she heard about Sedusa being caught.
Wicked Stepmother: Ima/Sedusa is this to the girls....or rather, might have, if the Professor married her.
Why Did It Have To Be The Dark?: In this episode, Bubbles is revealed to be afraid of the dark, which means the Professor has to leave the hall light on and crack the bedroom door open just a tiny bit so that Bubbles can go to sleep.
Wounded Gazelle Gambit: Sedusa pulls one on the Professor twice to get him to ground the girls. The latter one fails miserably due to her identity being exposed and she ends up arrested.
You Are Grounded: Sedusa, as Ima Goodlady, makes sure the girls get grounded so they wont interfere with her evil plans. She even says it word for word.