Ośniak

Ośniak was ogroid troll-like monster, to appear in the third game. However idea was later in development dropped likely because allready appearence of Rock trolls.

The Witcher 3: Wild Hunt
Ośniaks were supossed to appear in base game during its development in 2013 - 2014 but they were quckly removed and we would not know of all of this if not of leaked materials.

Informations from leaked materials
''Monster living in the forests or in the caves. It attacks in groups up to 4-5 members.''
 * Role in the group: Individual
 * Preferred behavior: aggressive - chases the opponent and attacks.
 * Special attacks and actions:
 * Strong attacks - his attacks are slow paced but deal high damage.
 * Charge - he charges and hits the player for high damage. Player can dodge / cast Quen to protect himself.
 * Eat a Nekker - if a Nekker is nearby, Ośniak can grab it and feed on it, which restores Ośniak’s health. After feeding (one bite animation) Ośniak throws adead Nekker (ragdoll) at his enemies. That attack deals small damage, but can stagger the opponent. 

Defence

 * none.