I've have nightmares about crocs like that.

When travelling in Northern Australia we were checking out a secluded billabong. I drove along one banks as we scouted for a camp site. On the other side of the water was a huge old dead tree lying in long grass. I pointed it out to the kids “hey, look at the big croc” … “yeah whatever dad”. As we drove back a few minutes later I saw that log stand up and slide into the water; without making a splash or a ripple.

We didn’t camp there, but it was a sobering reminder that there are some very big croc’s still around !