YMMV / How to Kill a Monster

• Alternative Character Interpretation: Was the monster genuinely evil or just attacking out of a combination of hunger and mistaken belief that the children were his captors? He did try to eat Gretchen even though he hadn't even finished his pancakes. It's not revealed if he saw the faces of the grandparents before he was trapped in the room. Despite being intelligent enough to speak, he makes no attempt to communicate with the children until the end. He shows sadism when he grins at Gretchen while she's begging him to let her go, though assuming he did believe the children were his captors and considering they tried to kill him twice, he has reasons to hate them at that point. Considering that he is capable of speech and deathly allergic to humans, they may have been able to reason with him had they known he could talk. Likewise, are the other monsters evil, or would they leave the children alone if not for the fact that they killed their brother?
• Ass Pull: The monster revealing he's allergic to humans. Considering he was inteliigent enough to speak, you'd think he'd realize his prey was toxic to him.
• Nausea Fuel: The book likes to emphasize how disgusting the swamp monster is. It does a pretty good job. It is described as having moss for fur with black beetles crawling through it (one of which it eats), a terrible odor, a mouth filled with bugs crawling across its disgusting yellow teeth and long, bumpy tongue, and eyes with worms swimming through them. The most disgusting part is when it licks Gretchen's arm.
• Nightmare Retardant: The monster speaking and revealing that it's deathly allergic to humans ruins the tension for some readers.
• The Scrappy: The grandparents are some of the most hated Goosebumps characters because of their stupid decisions and Skewed Priorities causing all the conflict.
• Slow-Paced Beginning: The plot with the monster does not start until literally the beginning of the second half of the book, though the book quickly picks up at that point.