Contrary to popular belief, this serpent did not normally strike in water; most victims were on dry land or a marsh island when they strayed into a snake run. These snakes only attacked when their "runs" were encountered, and then it bit with astounding quickness. A nathrach's critical strike was accompanied by a muscle poison that caused bleeding, bruises, and swelling . The venom was not very toxic but did cause bleeding, bruises, and swelling. It was designed to stun small rodents before the snake enveloped and crushed them.