This Unidentified Female Yogurt Jerk (played by Heather Haase) is a teenager who worked at a small restaurant selling yogurt in the Clamp Center lobby along with her co-worker, Alex. She seemed to be a rather bored individual who didn't work with much enthusiasm.
Some time prior to the gremlin invasion of the building, she worked late with Alex and they were both unknowing that the three hungry mogwai Mohawk, George and Lenny were feeding of some of the candies and yogurt. A customer asked her if one type of yogurt, the peanut buttercups, were all-natural and the she turned to Alex and asked if it was as she didn't know, whereupon he replied that he knew they were pesticide free. As they were talking, Mohawk's furry arm emerged from a batch of candies and caused one of the customers to yell out that it was a rat. An older man (played by the late great musician Jerry Goldsmith) came forth and asked if she really said it was a rat and Alex claimed she said that there was no rat, to downplay the situation. Then Mohawk emerged from among the candies and spooked them.
It is unknown whether or not she and other folks survived from annihilation.
As Billy Peltzer and his girlfriend Kate Peltzer (with Daffy inside of the box) arrived to the building moments afterwards, knowing that the mogwai had fed, the female yogurt jerk was seen jabbing at the candies with a pair of spoons, believing there were more of the strange furry creatures there.