Mr. Tedesco was the founder and director of Camp Atrocious, a summer camp that Chris and Dan attended when they were children. He acted as the main antagonist of episode Summer Camp and he was the first person that Dan ever took revenge against. He is voiced by Ernie Hudson from Ghostbusters.
Tedesco ran his camp by applying the methodology of "might is right", meaning that the physically strongest campers would prevail. Camp attendees would be split into one of two teams, the Warrior Wigwams or the Papoose Pavilion, and both teams would have to fight over the Spirit Stick, a wooden spear which signified which team had power and privilege to abuse the other team.
For two years since the camp's inception, the Warriors kept the Spirit Stick and constantly abused the Papoose, but this all changed when Dan arrived at camp for the first time. Upon first arrival, Dan had his things stolen by two Warrior members called Alec and Bobby, who also tied him to a tree, from which he had to be untied by Chris. In order to get his things back, Dan devised a plan to steal the Spirit Stick, which culminated with Dan throwing a nest of angry hornets into the Warrior cabin, injuring several of them before stealing the Stick.
Despite their rotund victory, Tedesco punished Dan and the Papoose for using "subterfuge and tactical superiority" instead of brute force to take the Stick, locking them in a tennis court as part of a "game" he called Civil War Prison Camp and intending to leave them there until camp concluded two weeks later. Dan devised another plan and dug a hole under the court fence, escaping with Chris one night to overthrow Tedesco's regime.
Dan and Chris subdued the Warriors with several traps in the woods before releasing the other Papoose and attacking Tedesco's cabin. A terrified Tedesco ran out into the woods but was soon captured and beaten by Dan, who stole his toupee and left him to the mercy of the other Papoose, who decided to play "William Tell" with Tedesco. His fate remains unexplained but it's implied by Dan that Tedesco did not survive the Papoose takeover of Camp Atrocious.
Tedesco was the first person that Dan ever took revenge against.
Dan states that before meeting Tedesco, he always followed the rules and laws that others imposed on him and Tedesco was the first person to ever teach him to stand up for himself when wronged. Dan took the lesson to heart and promptly stood against Tedesco for wronging him.