Nekkers - The Witcher 3

Take heed, gents, there's nekkers under this here bridge. If you all cross at once, without slowing or stopping, there's nothing to fear. But if your cart throws an axle and you get stuck out there... Well, close your eyes and pray to Melitele.
– Kurt Hammerbach, city guardsman in Vengerberg

A lone nekker is harmless. Five are dangerous. Ten can kill even a veteran monster slayer. Particularly troublesome are the larger, stronger individuals known as warriors, as well as the rare breed of nekkers known as phoocas.

Nekkers and phoocas live in the dark woods that grow in damp, mist-filled valleys, in colonies of one to several dozen individuals. They dig deep burrows for lairs and connect them with a network of narrow tunnels. Using these passageways they are able to move at great speed within and around their colonies.

Nekkers always attack in groups and by surprise. They try to surround their prey as quickly as possible, cutting off all escape routes. Luckily their attack is for the most part disorganized, for nekkers are not gifted with great courage and individual nekkers will often hesitate before overcoming their fear and striking. When fighting them one can use this moment of hesitation to kill the braver individuals before finishing off those who remain in the back.