The Orgone Accumulator

Grus varanus supernatet is a species of goanna-like crane native to Germany, where it is known as Schwebewaran. They're wholly invisible and live only in urban environments. Like sharks, they constantly need to be in motion to be able to breathe, and tend to live near freeways, sleeping on top of cars by taking them from one end of the freeway to the other, then switching to a different car, something they can proficiently do in mid-sleep.