You should avoid encountering screamers (Drekavac), as they can be scary and tricky opponents to deal with.

Screamers can only be encountered if you are walking during the night, so it's recommended to sleep at night and explore the world during the day.
They also won't attack the player first.

If you really want to find a screamer, there is a new quest available from a skeleton quest giver in Gambling Inn to kill one.