|Online Appearance?||Yes (as Mr. Swann)|
Stanley "Stan" Warren (called Mr. Swann in the online version) is Frank's boss at his workplace. He is only seen in Rodrick Rules and The Last Straw, despite this he is shown as one of the main antagonists of the third film.
In the books
In Rodrick Rules, he meets Frank with Bill Walter when going to the Winter Talent Show. Frank is not happy because he has to ride in Rodrick's van, which has his band name on it, something he does not like.
He later appears in The Last Straw, where Greg fears that Frank wants Greg to be more like Stan's sons, who are always fit. On Easter Sunday, Greg has a chocolate stain on his pants, and doesn't want to go into church that way, and since Susan won't let him skip it, Rodrick offers Greg his pants, but Mr. Warren then comes up and embarrasses Frank. Things get worse when Greg calls Manny "Ploopy" and makes him have a tantrum. Susan and the Heffleys have to leave after this since Manny won't calm down, and Mr. Warren sees Frank again with him walking out, embarrassing him even further.
In the film
He appears in Dog Days as an antagonist. He is said by Greg to host big July the 4th parties every year and went to the same Wilderness Explorers troop as Frank and owns his own scouting troop. He later appears near the end, where Greg gets his back along with his friends after he insults Frank secretly to his troop by calling him a "wounded gazelle". Greg then finds out that his camp has more luxury than Mr. Barrett's camp after he tries to hide ants under his bed as part of the plan, but they go all over him causing him to damage many of the tent such as burning the tent's cover. After Frank finds out about his luxury, he gets angry when he discovers he insulted Greg and his friends. He then fell over the honey trap and rolled down a slope, causing his head to land in a bee's nest. He is then mentioned by Greg that his troop disbanded and he now hosts a badminton team for kindergartners.