Abby Cadabby is the fairy-in-training Muppet from Sesame Street, the long-running children's television series where she debuted in 2006. Short clips of her bright voice circulate as memes because she sounds instantly recognisable to anyone who grew up with the show. This six-second 'they're here' moment, carried by her giggle, is shared for arrival jokes in the same way as the Noot Noot penguin greeting. It endures because the character feels warm and nostalgic, and the line fits any video where someone long-awaited finally walks in.