Contract: Strange Beast - Skellige
Quest Giver: Larvik Notice Board
Other Requirements: N/A
This quest can be started one of 3 different ways. The first of which is by visiting the Larvik Notice Board and accepting the contract and the second is by speaking with Thorleif (pictured above). Last but not least the most uncommon way to start the quest is by stumbling across the ambush site on the road or the end boss of this quest. Depending on how you began this quest your first few objectives may change, scroll down to where you began the quest if that's the case.
After speaking to Thorleif in town and accepting the contract he will direct you over to a few other survivors in the village. Speaking with them will update the quest and send you west along the path where you'll find an overturned cart. Investigate the bodies on either side of the road, the red clay behind the cart and the foot prints to update the quest.
Follow the footprints to a small cave just northeast of where you are now. Inside of the cave you should use Aard to blow away the poisonous gas or Igni if you wish to blow it up. You'll fight some Nekkers throughout the cave and a Nekker Warrior by the name of Hagubman in the back of the cave where the nest is.
Hagubman will borrow occasionally throughout the fight and summon regular Nekkers for you to fight in his absence. Take them out in order for him to resurface. Tip: Don't kill him too fast as you'll be able to loot Mutagens from all of the weaker Nekkers he summons.
Hagubman Weaknesses: Northern Wind (Bomb), Ogroid Oil