Although you might be tempted to think it was because he ate one too many Chalupas, it actually shows the power that TV personalities used to have. In December 1973, he went on his show and he said "You know what's disappearing from the supermarket shelves? Toilet paper? There's an acute shortage of toilet paper in the United States."
His words caused a widespread panic that made people run to the supermarket and buy up all the toilet paper they could find. Although he apologized for this the next day and explained it was all a joke, the hysteria he caused the day before led to an almost 3 week shortage of toilet papers!