This clip comes from a user-generated soundboard upload with no documented origin, so its source work, speaker and year are unknown. The spelling 'nmiggggweeerrrr' is simply how the uploader rendered the stretched yell. Short distorted vocal memes like this circulate widely because they are easy to drop into edits, and this one has found a small audience among meme editors who use warped yells as punctuation for fails and surprises. Its charm is its meaninglessness: with no quote or character attached, it works as a blank comic reaction that fits almost any chaotic moment.