Ultimately, it was the increase in the amount of cash that he was requiring that set off the alarm bells.

So Henry," Puck said as he kicked off his shoes and propped his smelly feet on the kitchen table. "I was wondering what you can tell me about puberty."
Henry turned pale and stammered.
Sabrina wanted to crawl under the table and die.

If only he can get over becoming a NERD.

Puck swung the cannon around in anger. The nozzle spun and hit Sabrina in the chest. The force was so pawerful she was knocked right off the platform and fell backward off the tower. She saw sky above her and felt the wind in her hair. How ironic, she thought, as she fell to her certain death, that at that moment she would have given anything to be a giant goose again.
Air rushed past Sabrina's ears and suddenly she felt her back tingling again. A moment later she was hanging upside down, inches from the ground. She looked up to find her savior, only to find that her her wasn't a person but a long, furry tail sticking out of the back of her pants. It was wrapped around a beam in the tower a kept her swinging there like a monkey.
Puck floated down to her, his wings flapping softly enough to allow him to hover.
"I bet you think this is hilarious. Look what you did to me with your stupid pranks. I have a tail!" she raged.
Puck's face was trembling. "I'm sorry."
"What?" Sabrina said blankly.
"I almost killed you. I'm sorry, Sabrina," he said, rubbing his eyes on his filthy hoodie. He lifted her off the tower and set her on the ground.
"Since when do you care?" Sabrina said, still stunned by the boy's apology.

That's the coolest thing I've ever seen," Puck said.
"How cool will it be when it kills us?" Sabrina asked.
"Considerably less cool," Puck replied.

That's why crazy people are so dangerous. You think they're nice until they're chaining you up in the garage.