Werewolf Mode is an extension for the Chrome web browser. When activated it responds to the current phase of the moon by changing the “hairiness” of the text on the page. At new moon, there is no hair on the text but maximum hairiness is at full moon.
The extension works by replacing the existing text with an algorithmically generated font based on a calculation of the moon phase.
The browser extension is not yet released into the wild, so to speak, as it is still undergoing safety tests to ensure it doesn’t run amok.