Before the month was out, Skidmore would develop a rock core and an impenetrable outer shield.

Much better, he said, to rely on defense - an impenetrable space-based shield.

I asked, to key him, to bring something else above the impenetrable shield he has constructed.

He can rearrange molecules in the air so as to create a virtually impenetrable shield about himself.

You know there is an impenetrable shield around the planet.

In fact, they say, what looked like an impenetrable shield protecting cancer cells turns out to be flimsy.

Years ago, his brother died when he dared to touch the surface of the impenetrable shield.

During his football career, this tireless fighter became an impenetrable shield, able to concentrate on what was needed.

For half an hour Radnor allowed his craft to drift within her impenetrable shield.

Wind and voices were woven into an impenetrable shield.