The 'Who Is She?' meme is a versatile reaction format often used to express feigned ignorance, jealousy, or genuine confusion. It gained significant traction through pop culture references, most notably Mariah Carey’s legendary 'I don’t know her' interview and various reality TV snippets where a character reacts to a potential rival. Online, the phrase is frequently paired with images of people looking intensely at their phones or glaring at a screen. It has evolved into a staple of stan culture and social media shade, perfect for questioning the sudden appearance of a new person or trend in a humorous, theatrical way.