His eyes strained as though seeking view of an invisible object.

He grips two invisible objects, one in each hand, and turns them.

There are no invisible objects by association; the supply is strictly limited.

He can even locate invisible and intangible objects this way.

For one, it can see through walls, invisible objects, and such.

There was something in the middle of the air, a strange, invisible object which blocked his way.

Her hands curled slightly, as if she were clutching a solid but invisible object.

The invisible object was in his outstretched arms again (he could feel it).

Also special invisible objects, called emitters, are often used to create environmental effects, such as fog and mist.

Three men onstage appear struck in the eye by an invisible object.