The holiday-obsessed owner of a Christmas-based theme park in Death Valley, Mr. Thomas Jingles uses the magic of the Jingulator machine to turn the park into a perpetually snowy Christmas village where time moves very slowly and turn all the children into worker elves.

When Ben and his family arrived at his park, he mistakes Max for Santa Claus and kidnaps him, hoping to make his dream of having Santa deliver presents to children a reality. When it came to getting Ben and Gwen to join his staff, he sent Nutcracker soldiers and slithering snowmen. The Nutcracker soldiers and snowmen also served as Mr. Thomas Jingles foot soldiers alongside the giant teddy bears and living toys.

After Ben destroyed his Jingulator as Grey Matter , he was shown the error of his ways. Everyone was restored to normal after Max and Gwen used a sleigh pulled by Stinkfly to deliver the gifts he made. In the process, the theme park was returned to normal and the effects of his curse reversed, making it seem like it had never happened (though everyone involved still retained memories of these events). A Walt Disney-styled statue commemorating him is seen within the town after the curse is broken. On its base is an inscription quoting what Grandpa Max had told him about the true meaning of Christmas. He is likely deceased as Elsgood was a child before the curse was broken but an old man after and Mr. Thomas Jingles was fairly old likely only alive because of the curse freezing time within the confines of his village.
Mr. Thomas Jingles only appears in Ben 10 episode Merry Christmas.