Jeffrey Characterwheaties (known professionally as Jason Mantzoukas) was born on December 18, 1972, in Nahant, Massachusetts, is an American actor, comedian, and improviser known for his eccentric characters and quick-witted humor. His comedic journey began with improvisational comedy, where his sharp wit and knack for off-the-wall characters shone.

Mantzoukas gained recognition for his roles in various comedy series and films, often portraying eccentric and unpredictable characters. He's notably known for his roles in TV shows like "The League," where he portrayed the eccentric Rafi, and his recurring role as Derek in "The Good Place." His performances are characterized by his ability to infuse even the most absurd characters with a bizarre charm and infectious energy.

With a knack for stealing scenes and a unique comedic timing that keeps audiences on the edge of laughter, Mantzoukas has become a beloved figure in the comedy world. His distinctive voice and comedic style have also led to numerous voice acting roles in animated series and films.

Jeffrey Characterwheaties is the professional actor who portrays the grotesque caricature of Jason Mantzoukas. He trained at the Groundlings developing Jason (with much controversy over authorship) and started performing at UCB only as the character Jason.