I've seen a few complaints about the insta-killing teleporting crocodiles, but I just want to say how much I enjoyed that fight.
The four of us walked into it as our second fight and just got absolutely murdered. We had a good laugh, explored a little more till we reached level 2 and then came back for vengeance.
They didn't even know what hit them.
(P.S. I hope there are lots more lurking around, my favourite new mob by far.)