Frank created the character in ("The D.E.N.N.I.S. System") In the episode, Mac compared Frank's sexual gains to feeding like a "mantis." Frank liked Mac's word choice, and requested to Dennis and Mac to call him mantis, but Dennis refuses his request. Later in the episode, Dennis asked Frank to pose as a carney at a fair. Instead of a carney however, he shows up as made up doctor named "Mantis Toboggan".
Frank once again assumed the moniker in a misguided attempt to make a "viral video" for Paddy's Pub to increase their web presence. Frank mistakenly thought the concept was a "virus video" centered around an actual virus, and used Toboggan as a central figure to proclaim that people who came to Paddy's would be "infected". ("The ANTI-Social Network")
While the gang is attempting to break Wade Boggs' alleged beer drinking record on a cross-country flight, Frank gives another passenger a potentially lethal dose of sleeping pills to prevent him from diminishing the on-board beer supply. When the passenger begins to experience severe symptoms, the stewardess calls for a doctor. A drunken Frank approaches and introduces himself as "Mantis Toboggan." ("The Gang Beats Boggs") He claims to also be a pilot.