Walter Wisdom was an old friend, arch enemy and former college roommate of Doc Brown. He was the host of the popular kids show Mr. Wisdom (unlike the clowns on Guiding Light and Bewitched) and the inventor of such things as the Perpetual Motion Hula Hoop.
A Trip in the DeLorean
While he was visiting Lone Pine Mall, Walter Wisdom came across Marty and Verne. He went back to Doc's laboratory, where he found the DeLorean time machine. Doc chased him out of the lab with a Heat Seeking Rat Trap, however Wisdom returned to the lab later that evening. He stole the DeLorean, a Rainy Day Sunshine Umbrella, a machine that makes peanut butter inside the shell, the Memory Archive Recall Indexer and Enhancer with intent to sell them all and make himself a profit. He took the DeLorean to Ancient Egypt, only to find Doc, Marty, Jules and Verne in hot pursuit in the Time Train. They linked the DeLorean to the Train by means of a Time Tow Linkup system, and became dragged to the Island of Krakatoa on the morning of August 26, 1883. Wisdom disconnected the DeLorean from the Train, and the Train and its occupants landed inside the exploding volcano.
Personality and traits
Oddly enough when not in disguise he sounded a lot like Biff Tannen and had yellow eyes and teeth, the two traits most Tannens all seemed to possess. However it is unknown if there is any connection to Wisdom and the Tannens.