…attacking lines of the enemy infantry are men like ourselves; but these tanks are machines, their caterpillars run on as endless as the war, they are annihilation, they roll without feeling into the craters, and climb up again without stopping, a fleet of roaring, smoke-belching armour-clads, invulnerable steel beasts squashing the dead and the wounded—we shrivel up in our thin skin before them, against their colossal weight our arms are sticks of straw, and our hand-grenades matches.
There are no more uses of "invulnerable" in the book.
Show samples from other sources
When this world is sealed, I will not just be invulnerable; I will live forever.
Cassandra Clare -- City of Heavenly Fire
They walk in the dark, along the edges of high cliffs, humming to themselves, thinking themselves invulnerable.