The worm grew to adult size within it, but it needs to get into water in order to mate, and it does that by releasing proteins that addle the cricket's brain, causing it to behave erratically.
O verme cresceu dentro dele, mas necessita entrar na água para acasalar, e faz isto ao liberar proteínas que desorienta o cérebro do grilo, fazendo com que se comporte de forma errática.