The self-published picture book The Rabbit Who Wants to Fall Asleep, by Carl-Johan Forssén Ehrlin, sold more than 29,000 print copies at outlets that report to Nielsen BookScan last week, making it the #2 juvenile fiction title for the week ended August 23.

The sales jump for the picture book, released through Amazon's CreateSpace, was one rarely seen in publishing. At the close of last week, on August 16, the book had only sold 24 copies through BookScan outlets, and had sold just over 300 copies since its release in April 2014.

The book, which claims it has the ability to quickly send children to sleep, hit the Amazon bestseller lists last week, starting in the U.K., where media reports there fueled sales that eventually spilled over to the U.S. and other global markets.

The Stockholm-based Salomonsson Agency signed Forssén Ehrlin last week and world English rights to the book (along with two sequels) are rumored to have be bought by Random House in a seven-figure deal. A spokesperson for the publisher would not comment on the acquisition.

No one associated with the book has explained why sales of Rabbit skyrocketed so suddenly, sending the book to the top of Amazon's U.K. print list. The author has largely avoided media requests since speaking with the Daily Mail, which first reported on the book on August 14.