“Never play leapfrog with a unicorn”
“Leapfrog” (or “leap frog”) is a children’s game where one player jumps over another’s stooped back. The game has been played on playgrounds for hundreds of years.
“Never play leapfrog with a unicorn” is a jocular one-line saying; landing on a unicorn’s horn would make the game of leapfrog very painful. The saying broadly means that one should not take unnecessary risks and flirt with danger. “Never play leapfrog with a unicorn” has been cited in print since at least the early 1970s and has been printed on gift items such as T-shirts, bumper stickers and posters.
Wikipedia: Leapfrog
Leapfrog is a children’s game in which players vault over each other’s stooped backs. Games of this sort have been called by this name since at least the late sixteenth century. They also played this in colonial America.
Google Books
The Elevator Constructor
Volumes 70-71
1973
Pg. 21:
Remember, never play leap frog with a Unicorn!
Google NewsArchive
16 November 1974, Evening Independent (St. Petersburg, FL), ‘The Hunt” by Jon Wilson, pg. 1-A, col. 3:
The letter was never answered, and for such cavalier posture, may the commission, both collectively and. individually, one day have occasion to play leapfrog with a unicorn.
10 March 1975, Kossuth County Advance (Algona, IA), Don Smith column, pg. 5, col. 1:
A true, wise man never plays leap frog with a unicorn.—Benacek.
Google Books
Invasion of the Clones
By Joseph Rosenberger
New York, NY: Pinnacle Books
1976
Pg. 113:
“And before you blow your stack, Doctor, just remember .that a truly wise man never plays leap-frog with a unicorn. You dig?”
Google Books
Murphy’s Law:
Commandments and corollaries of Murphy’s original law of inevitable disaster, dedicated to the dismalness of human nature and the certainty of cruel fate
By Jim Russell
Millbrae, CA: Celestial Arts
1978
Pg. 88:
Never, never play leapfrog with a unicorn.
Google News Archive
27 July 1979, Youngstown (OH) Daily Vindicator, “Debacle for Dems Feared” by Victor Riesel, pg. 26, col. 4:
WASHINGTON—As this capital’s most senior politician, George Meany, labor’s chief of chiefs, long ago learned he mustn’t play leapfrog with a unicorn.
Google News Archive
24 June 1980, Southeast Missourian (Cape Girardeau, MO), “There are laws, and then thereare laws…” by Mark Bliss, pg. 2, col. 5:
Murphy has other words of wisdom. Such as never play leapfrog with a unicorn.
OCLC WorldCat record
It is unwise to play leapfrog with a unicorn.
Author: Book Arts Press.
Publisher: [New York] : Book Arts Press, 1985.
Series: Book Arts Press thought for Valentine’s Day.
Edition/Format: Book : English
OCLC WorldCat record
Don’t play leapfrog with a unicorn : let’s be friends
Author: Wiliiam Earl Stowell; Ferne A Stowell
Publisher: Paradise, Ca : Earl Stowell, 1993.
Edition/Format: Book : English
OCLC WorldCat record
Never play leapfrog with a unicorn
Author: David Kitchen; Nick Sharratt
Publisher: London : Heinemann Young Books, 1995.
Edition/Format: Book : Juvenile audience : English
OCLC WorldCat record
Never play leapfrog with a unicorn : bumper stickers from the information superhighway
Author: William Ramwell; Arthur Goldstuck
Publisher: Frenchs Forest, N.S.W.: New Holland Publishers, 1997.
Edition/Format: Book : English
OCLC WorldCat record
Never play leapfrog with a unicorn : a coming of age slice of a farcical life
Author: F W Bosworth
Publisher: Victoria, B.C. : Trafford, ©2003.
Edition/Format: Book : Fiction : English