Juli Clover at MacRumors, discussing Siri’s appearance in the yet-announced OS X 10.12:
In the menu bar, there’s a simple Siri black and white icon that features the word “Siri” surrounded by a box, while the full dock icon is more colorful and features a colorful Siri waveform in the style of other built-in app icons. Clicking on either of the icons brings up a Siri waveform to give users a visual cue that the virtual assistant is listening for commands, much like on iOS devices when the Home button is held down.
I dig the Dock icon, but I sure hope that menu bar icon is still a placeholder.