The "Pizza Dude" is a delivery man for the local Hinkley Hills pizza restaurant.
Ricky Butler orders at least ten pizzas to feed his friends who have attended his party. After Steve asks if he can go to McDonald's and get some quarter pounders, Ricky rebuffs him, stating that "the pizza dude's coming!" He repeats this several times in a successful attempt to get his friends to stay at the party.
Staying true to Ricky's words, the pizza dude does eventually arrive. Since a cul-de-sac has only one way out or in, the pizza dude was heading down the main road. Because Ray Peterson was grabbing Hans Klopek in the ambulance to attract attention to him being attacked, Hans swerved towards the pizza dude. In turn, the pizza dude swerved and hit a tree, spilling the pizzas out the side. Ricky can be heard faintly shouting "pizza dude!". The ambulance then ran into Art Weingartner's house and later set it on fire.
The pizza dude actually wound up foiling the Klopek's escape, probably saving Ray's life.