The most popular novelty item of 1972 was the "invisible dog on a leash."
Credit for its invention goes to S. David Walker (the "S" stood for "Sir"), who in addition to being a mindreader and carnival pitchman was a prolific inventor of weird, useless stuff.
He first got wealthy selling Clackers
— plastic spheres attached to a string which made a clacking sound when knocked together. Then he came up with the Invisible Dog on a Leash. According to a May 1, 1983 profile of him in the Salina Journal
The invisible dog came along when a fellow novelty dealer stuck with 5,000 broken child-sized rodeo whips asked Walker if he could think of any use for them. Walker stopped klacking long enough to attach a tiny dog harness to a whip's stiff handle. Two million were sold — 300,000 by Walker and the rest by imitators.
But the real moneymaker for Walker was his later invention of metallic balloons, which soon became more popular than everyday rubber balloons. Although, again, imitators eventually ended up making more money from them than he did.
Strangely, there seems to be almost no recognition of Walker's status as an inventor (except for that one article in the Salina Journal
). Not even a wikipedia page about him.
Life - July 21, 1972
The Columbus Republic - Jul 14, 1972
Sedalia Democrat - Sep 20, 1972
Fort Myers News-Press - Nov 12, 1972