As soon as Arthur walked into Mr. Ratburn's classroom, all the other kids knew something was different about him.

"You, uh, parted your hair the other way," Buster guessed. Arthur shook his head and smiled.

"You cleaned the gunk from your ears," said George. Arthur shook his head again.

"You got new pants," said Muffy. Arthur nodded.

"No fair," Buster complained. "You're a girl." Muffy stuck her nose up.

Now everyone noticed that Arthur was wearing a new pair of brown corduroy pants. But that wasn't all...

"Those pants are a size bigger," Francine pointed out. "You're gaining weight, Arthur."

The aardvark boy patted his belly proudly as he seated himself at a desk.

Mr. Ratburn delivered an interesting lesson about blood cells, and then the kids started to file out of the classroom.

"When I said he's gaining weight," said Francine to her friends as soon as Arthur had strolled out of earshot, "what I meant to say was, he's turning into a giant marshmallow."

"Or maybe a small hippopotamus," Buster added.

"So he's a little fat," Sue Ellen chimed in. "Big deal. I've lived in places where I was surrounded by starving people."

"By process of deduction, I've arrived at the conclusion that Arthur has been eating too many of his dad's sweets," Fern proclaimed.

"Fern's right," said Muffy. "We need to put Arthur on a diet."

"But how do we do that?" asked Jenna.

"No problemo," said Binky, raising a fist. "I'll just follow him around and clobber him whenever he tries to eat junk food."

"We could force-feed him a box of Buster Clusters," Francine suggested. "That would take away his appetite for a week."

"Hey!" growled Buster.

"Perhaps we're approaching the problem from the wrong direction," said Brain analytically. "Exercise is another effective way to lose weight. If Arthur walks for two hours a day at three miles per hour, then he burns 500 calories per day, or 3,500 calories per week, which is the equivalent of..."

"Shut up, Brain," Muffy grumbled.

"So how do we get Arthur to exercise more?" asked Fern.

Binky started to raise his fist again, but the other kids glared impatiently at him.

Sue Ellen's face lit up. "I've got an idea."

Morning recess came along, and Arthur was sitting on a bench by the playground, munching a cream puff that his dad had placed in his lunch box. Binky approached him, glancing about furtively.

"Hey, Binky, what's up?" said Arthur.

"Shh!" whispered Binky. "She'll hear you."

"Who?"

"Sue Ellen," Binky muttered quietly. "I took a peek in her diary while she wasn't looking. She's in love with you, Arthur. That's all she writes about. She wants to hug you, and kiss you, and...oh, no, here she comes!"

Binky fled quickly, and Arthur marveled at the story he had told. What if it was true? It was unthinkable...

A moment later Sue Ellen arrived at his bench. "Arthur, have you seen Binky?" she asked.

Seized by terror, Arthur leaped to his feet and ran away with all his might, screaming. He didn't stop until he was halfway to his house.

Sue Ellen picked up the cream puff that Arthur had left behind, took a bite out of it, and walked off, humming and chewing.