While other accountants kept reliable ferns on their desks, Potter kept a jug that he spat in while he cooked the books. Every few weeks, he would pull something alive from the mud in the jug. Often the prize would be a worm, in which case Potter would present it to the boss, a weekend fisherman, who would discreetly flush it down the toilet. Once, Potter pulled out a spider. He set it free at the base of his desk to catch mosquitoes. The spider ran off.
One Spring afternoon Potter spotted a pink pencil eraser poking out from the mud inside the jug. He moved the jug under his desk lamp for light. Soon, the eraser sprouted a dozen yellow hairs.