Be weary that these creatures use invisible frequently, so you may run into more than you think when approaching them. Despite staying invisible for a short amount of time, if grouped, their combos can bring down even decent skilled players.
Treat them like a dragon and watch out for the waves. They are pretty easy. When there are 2, try to make them face each other so they hurt each other with the waves. Use the same strategy when fighting one with a Bog Raider.
Knights: Should move in fast before their waves can do damage to you, and make sure you retarget it once it has become visible. It is strangely much better to take on 1 Mutated Tiger than 2, because it's less hard to avoid their waves this way, and you rarely need to Exori as you often deal strong enough damage anyway.