The clip comes from Critical Roll Campaign 2, Episode 117, where dungeon master Matt Mercer voiced a creature with a distinctive rolling trill. A fan clipped the moment and uploaded it to a soundboard, noting it was too good not to share. From there it circulated among tabletop roleplay fans who needed a quick, human-performed monster vocal for their own videos. It endures because Mercer’s creature voices are widely imitated, and this two-second trill is instantly usable as a practical monster cue without any editing.