The Enclosed Instruction Book is a Mario's ultimate weapon. It was forged long ago by the Ancient Geeks and is rumored to be sentient, but little is known about it since it interferes with recording mechanisms on most spacecraft. It takes no side in battle, but instead protects warriors of both good and evil; studies have shown that, without it, the Mushroom World would be constantly terrorized by threats such as intense solar wind and devastating meteorites. Not to be mistaken for the all spark.
Because of its mighty electric power, few have been able to survive touching the Enclosed Instruction Book. It is said in legends, however, that Mario once did and somehow lived, albeit changed forever; jolts of Instruction-energy morphed his catchphrase from "It's-a me, Mario!" to "If you need instructions on how to get through the hotels, check out the Enclosed Instruction Book."
The Instruction Book is featured in the final level of Super Weegee Galaxy, Bowser's Enclosed Instruction Book Reactor. The game reveals that Bowser was attempting to harness the Enclosed Instruction Book's power and use it with the evil intentions of forcing the Mushroom World's people to buy him doughnuts or DIE. In an epic battle atop the "Enclosed Instruction Book Reactor" with which the Koopa King was attempting to harness the Instruction powers, though, Weegee was able to defeat Bowser, who was sent plummeting, ironically, into the depths of the Instruction Book itself, which consumed him. He was later regurgitated, though, because he forgot his deodorant.
It is also an enemy of the King's infamous Dinner Blaster.