Just as bacteria have evolved resistance to many of the antibiotics once used to kill them, modern bedbugs are almost invulnerable to at least some insecticides.
Moreover, he was a boy whom no man could hurt; an invulnerable and dodging serpent who, when chased into a corner, flew out again between his captor's legs, scornfully yelping.
Margaret's voice was so soft, and her eyes so pleading, that Mrs. Thornton was for once affected by the charm of manner to which she had hitherto proved herself invulnerable.
This endoskeleton makes the Terminator all but invulnerable to most small arms fire, and it has proven extremely resistant even to military-grade assault rifles in the 5.56 and 7.62mm calibers.