"Shah Guido G." is a science fiction short story by American writer Isaac Asimov.^[1] It was first published in the November 1951^[2] issue of Marvel Science Fiction and reprinted in the 1975 collection Buy Jupiter and Other Stories, where Asimov explains his love of puns. It is an example of a shaggy dog story, as indicated by the title ("ShahGui doG").

Shah Guido G. is the nickname of Guido Garshthavastra, the hereditary Secretary-General of the United Nations ("Sekjen"), a tyrant who rules the Earth from a levitating island called Atlantis.

Philo Plat is an aristocrat who secretly plots Shah Guido G.'s downfall. When he learns that the stations that power the Sky-Island's anti-gravitational beams are close to critical, Plat convinces Shah Guido G. to order in a division of Waves (female shock-troops whose name derives from the WAVES of the United States Navy) to put down a supposed rebellion by the technicians.

As Plat suspected, the weight of the Waves' cruisers is sufficient to overload the Sky-Island's power generators, causing it to plummet to the ground, thereby liberating the people from tyranny. The story ends with the punning punchline: "Why, once more in history, Atlantis sank beneath the Waves."

• Asimov, Isaac, Buy Jupiter and Other Stories, Fawcett Crest, New York, 1975, pp. 33–44. In his background notes on page 42, Asimov himself defines the tale as a shaggy dog story, and lets the reader in on the "Shahgui (shaggy) Dog" pun in the title.

• Shaggy dog story

• Shah Guido G. title listing at the Internet Speculative Fiction Database