Why is doge on Twitter? What you should know about the crypto icon, Elon Musk.

On Monday, Twitter’s blue bird icon disappeared from the top of the website and was replaced by the head of an enigmatic-looking shiba inu dog.

But it is no ordinary shiba inu. Rather, it depicts “doge” — a meme that has come to represent a cryptocurrency with which Elon Musk, the billionaire who bought Twitter for $44 billion in October, has had a long and complicated history.