An extension change your avatar on haxball for a second, this is useful to call for the ball or just show some emotion!
5,6,7,8,9 are the default keys but these can easily be changed by clicking the extension icon. This is a very barebones extension and limited knowledge of JSON is required to change the avatar set. As far as I’m aware, this is not against any TOS however, I do not accept responsibility for any damage caused by this script.