The line comes from Matt Berry's performance as Laszlo Cravensworth in the FX comedy series What We Do in the Shadows, which began in 2019 and is based on the 2014 film of the same name. Berry's Laszlo is a flamboyant, centuries-old vampire whose grand, old-fashioned manner makes even ordinary scoldings sound dramatic. Short clips of his delivery circulate on soundboards and in fan edits because the phrase is instantly usable as a reaction. It endures because it captures his character in a few seconds and fits almost any moment when someone needs to be stopped.