In "Not What He Seems," Soos is seen ordering at the drive-thru, asking for anything "that comes with a free toy." As he is ordering, he is interrupted by a call from Stan Pines. At first, Soos is confused, thinking that Stan was talking to him through the man shaped microphone, wondering if it is "some sort of possession situation," before realizing that it was coming from a walkie-talkie in his truck. After Stan explains that he needs Soos to go to the Mystery Shack to guard the vending machine, Soos agrees to help, and then disconnects. He adjusts his hat, stating that it's "time for a repair guy to become a repairman," before the employee at the drive through hands him his "Junior Yum-Yum Baby-Time Kiddo Meal." Soos tells the man to "just put one in [his] mouth," and the employee does as instructed without question.
The restaurant is styled like a log cabin. There is a giant ax lodged into the roof, with the company name written on the ax's handle in big letters. The name is a portmanteau of the words "Yum" and "Lumberjacks."