Les Waas, the advertising legend behind the Mister Softee jingle heard in hundreds of ice cream trucks for more than half a century, has died. He was 94.

Waas died April 19 at Abington Hospice in Warminster, according to Goldsteins' Rosenberg's Raphael-Sacks funeral home.

The Mister Softee song, originally written in 1960 for the company started in his Philadelphia hometown just a few years earlier, played in the company's ice cream trucks as a way to signal their approach. Soon, the song became ubiquitous with ice cream, summer and fun as the opening notes became instantly recognizable to anyone within earshot - sparking a craving they didn't realize existed.

Both loved and loathed, the jingle remains a lasting part of the collective American childhood.

The tune has also been used by competitors to lure children out of their homes and into the streets for frozen treats. During his advertising career, which spanned more than five decades, Waas wrote and produced more than 970 jingles for advertisers, according to the Broadcast Pioneers of Philadelphia - where he served as president and chairman of the board.

The Mister Softee song, officially titled "Jingle and Chimes," is his greatest legacy. Although most people know the notes of the twinkling, looping cadence, the song also has lyrics, including: "The creamiest dreamiest soft ice cream you get from Mister Softee" and "Listen for my store on wheels ding-a-ling down the street."

Mister Softee has over 600 trucks and over 350 franchise dealers operating in 15 states plus China.

Waas was also known for his sense of humor. University of Calgary psychology professor Piers Steel wrote in a 2011 "Psychology Today" article that in 1956, Waas and some of his fellow admen posted a sign in a Philadelphia hotel reading, "The procrastination's club meeting has been postponed." The sign drew attention from local press, prompting Waas to eventually hold the meeting - the start of a long-running prank. Waas served as president of the Procrastinators Club of America, which even today claims thousands of members.

Waas' wife, Sylvia, died in 2006. He is survived by his children, Sherri Waas Shunfenthal and Murry Waas.