Evolution leads to some surprisingly sophisticated survival techniques... especially when it comes to symbiotic and parasitic relationships.

Consider the example of Ophiocordyceps unilateralis: https://en.wikipedia.org/wiki/Ophiocordyceps_unilateralis (or not, if you have a squeamish disposition, especially in regards to zombies).

Fortunately, as Douglas Adams reported, babel fish pose no danger to their hosts (as long as you don't take their existence as proof of God, and subsequently get run over at a zebra crossing).