"Don't judge a book by its cover — it's a lesson we're taught from an early age, and with good reason," the mother, Ariane Beeston, wrote in Essential Baby. "But what happens when you accidentally do?"
She scrolled through 452 search results for her 9-year-old son, according to the mother.
Finally, she settled on a book simply titled Penguins.
"A collection of interconnected short comic strips by The Unicorns singer that, without words or Homo sapiens, showcases the human condition," the description reads.
"The debut graphic novel by musician Nick Thorburn [Islands, the Unicorns, Mister Heavenly, Serial], Penguins is a series of interconnected short comic strips that, sans words or human characters, showcases the breadth of emotion we as humans experience. Black & white illustrations with some colour."
"I love the human condition!" Beeston said. "How educational! How delightful! And it's a comic!"
She clicked "add to cart" almost immediately.
But when it finally arrived in the post two days ago, on June 17, she found something a little different to what she was expecting.
"Instead of cute, comic, penguins, as I flicked through the increasingly odd [but cool!] drawings, there, between the pages, I found an exploding phallus," the shocked mother wrote.
"An. Exploding. Phallus."
Amused, Beeston described the drawings as "cool" and got in touch with the book's author to share her interesting experience.
"Haha. Wow. Omg so sorry!" the book's author Nick Thornton replied. "Hopefully you get something out of the book."
Beeston reckons it's not an entirely wasted experience.
"It will make a cracking story to tell my son," she said.
"When he's a little older that is …"