YMMV / The Girl Who Cried Monster

• Big-Lipped Alligator Moment: There are several pages describing a character using a (fictional) frisbee-like toy. The book puts so much focus on it, you'd think it would be some kind of Chekhov's Gun, but it's never brought up again, and we never find out what the point of lingering on it for so long was.
• Designated Villain: According to the Goosebumps podcast, Goosebuds, Mr. Mortman may qualify. Yes, he's a monster that eats his turtles and live fish but he does this AWAY from people. He doesn't actually seem to be hurting anyone. The only time he does anything threatening is when he can't allow Lucy to leave, however, this is kind of justified because he doesn't want to be exposed as a monster who, again, didn't hurt anyone. When Lucy's parents eat him, this could qualify as an Alas, Poor Villain moment.
• Memetic Mutation: Lucy's "Life is just a phase I'm going through" is constantly posted on tumblr.
• Moral Event Horizon: Mr. Mortman eating his own crickets, turtles, and pets is one thing because he owns them. Trying to kill Lucy for trying to get proof that he is a monster is quite another. He knows that no one would believe Lucy because she has a reputation for making up monster stories, something he even laughs about when she asks if there are any in Anne of Green Gables. All Mr. Mortman would have to do is report to the police that Lucy is stalking him, and he could get a restraining order. Indeed, Lucy's parents are horrified when Aaron witnesses the murder attempt and convinces them that Lucy is telling the truth this time. See Designated Villain above.