Errei fui muleca is a misspelled, feminised variant of the Brazilian Portuguese expression errei fui moleque, which roughly translates to I messed up, I acted foolishly. Clips using the phrase circulate on Brazilian social media and messaging apps as a ready made confession for everyday errors. Its popularity comes from how specific it sounds: short, recognisable to Portuguese speakers, and instantly understood even without subtitles. Outside Brazil it is mostly shared as an opaque but funny reaction sound for fails, bloopers and self deprecating edits.