On Monday, Twitter users suddenly found a dog’s head in their profiles instead of the usual logo with the blue bird. The online service switched to the image, which stands for the controversial digital currency Dogecoin, without any explanation.

Twitter owner Elon Musk has often mentioned the cryptocurrency, which was originally intended as a joke, over the years and therefore has to defend himself against an investor lawsuit.

The Dogecoin price, which has been in the basement for a long time, temporarily jumped by around a fifth after the logo change. Even after that, however, a unit of the digital currency only cost around ten US cents. At its peak in spring 2021, it was over 60 cents for a short time.

After the price collapse, an investor sued Musk, alleging that he was part of an illegal Ponzi scheme in which the price of Dogecoin was boosted and then crashed.

Musk’s lawyers last week filed for the lawsuit to be dismissed, reiterating that the cryptocurrency is a legitimate investment with a total value of around $10 billion. Dogecoin has existed since 2013 and has the image of a dog of the Japanese breed Shiba Inu as its logo.