"Hi, I'm Cookie Masterson, and only you can prevent forest fires... Seriously, it has to be you. I'm sure as hell not gonna do it."
- Cookie Masterson, You Don't Know Jack 2015
Cookie Masterson has appeared in several You Don't Know Jack games since the series began. For the first three installments, he served as the sign-in host for players. Starting with Movies, Cookie began hosting games and would go on to become one of the most regular hosts in the series. Starting with the 2011 version, Cookie became the permanent host of the show and has hosted every game since. Cookie's involvement with the series has grown since then, with question-types and sponsors themed around him and even introducing his ventriloquist puppet Billy O'Brien to read questions.
Cookie has hosted all games of Fibbage since the original standalone release. In each installment, Cookie reads out a little-known fact with a word missing that players then need to fill in with a convincing lie. Keeping with his style of humor that he developed in You Don't Know Jack, Cookie may occasionally make a witty remark about the fact, mock other players lies or call everyone out for missing the truth. If a player takes too long to select a category, Cookie will grow impatient and pick one on their behalf.
Cookie is the host of Fakin' It. In this game, he will send a prompt to all but one player's device, with the player who didn't get a prompt having to avoid being caught out. Cookie does very little in this game compared to other titles, though he may make snark remarks when players' choose the wrong person as 'the faker' or for failing to unanimously agree.
Cookie makes a cameo appearance in Trivia Murder Party. There is a random chance that the host's voice filter will turn off and reveal his true voice; one of these voices is Cookie's.