Grawlix is a term used to describe the symbol strings of typography that replace profanity, such as “%*#$*@”. The term was coined by Mort Walker, an American cartoonist, in 1964. Walker is best known for creating the comic strip Beetle Bailey in 1950 and Hi and Lois in 1954. He was actually born in El Dorado, Kansas in 1923 and grew up in Kansas City, Missouri. Six of his nine children still work for him in his Connecticut studio where he continues to supervise at the ripe age of 89 years old.
In his book The Lexicon of Comicana, written in 1980 as a satirical look at the devices cartoonists use, Walker invented a vocabulary called Symbolia. For example, Walker coined the term "squeans" to describe the starbursts and little circles that appear around a cartoon's head to indicate intoxication.
The typographical symbols that stand for profanities, which appear in dialogue balloons in the place of actual dialogue, Walker called "grawlixes."