The line comes from Adventure Time, the Cartoon Network series created by Pendleton Ward that ran from 2010 to 2018. The Lich, voiced by Ron Perlman, is the show's ancient undead antagonist and Finn and Jake's most feared enemy, known for speaking in short, grave commands rather than long speeches. Short clips of his voice circulated on soundboards and in fan edits because one word could sum up his whole presence. It remains popular as a reaction clip for defeats, collapses and moments where something is about to go badly wrong.