The Cosmic Master Thief

They say that somewhere in the boundless sea of stars, there is a vast interstellar empire;

They say that the empire's territory stretches across hundreds of star systems;

They say its planets are home to humans, people with sunflower heads, dogs with human heads, and creatures whose heads are bigger than beds;

They say all those bizarre beings have had something stolen from them;

They say the thief has already stolen his way across billions of light-years.