Usada Pekora is a Japanese VTuber with Hololive who debuted in 2019 as part of its third generation, known for her mischievous rabbit persona and loud reactions during game streams. Clips of her screams were widely shared on YouTube and social media, and her iyaaa became a shorthand reaction among fans, similar in use to an anime wow moment but far more panicked. The clip spread beyond her live audience into edits and soundboards because its short, distinctive shriek expresses flustered surprise without needing any context from the original stream.