Ocean and River Monsters, etc.

http://www.diffen.com/difference/Octopus_vs_Squid,
http://www.youtube.com/watch?v=v_uU8PaqJ9g, http://www.youtube.com/watch?v=HdNAht0oYjQ

Although more mysterious than paranormal, these are certainly some of the most dangerous creatures in the world.
http://en.wikipedia.org/wiki/River_Monsters#Season_4:_2012,
http://www.youtube.com/watch?v=tfd5p1JqUsw,
http://animal.discovery.com/tv-shows/river-monsters,
http://www.youtube.com/watch?v=FMIN0XVKfPE,
https://www.facebook.com/RiverMonsters,
http://www.youtube.com/watch?v=LudndCm70lY

Lots of people like to eat things that are still alive.
http://www.youtube.com/watch?v=oNy8MUPOAtQ,
http://www.youtube.com/watch?v=-4RmkdAoQB0
And when various creatures are large or fast enough, they will eat people.
http://scifi.stackexchange.com/questions/18002/how-did-the-black-liquid-work-in-prometheus

http://tech.ca.msn.com/animal-imposters,
http://paranormal-intersection.blogspot.ca/2012/05/worms-eels-and-sea-snakes.html