Thought Stealers are among the first creatures players will encounter upon entering the Warrens. Several of them will appear out of nowhere, together with four Hopping Vampires. One group will appear in front and one group behind players who go down the path into the first room of the Warren. Thought Stealers are suicidal creatures, who will chase players down and when coming into touch range kill themselves, draining all their energy.
- While less dangerous than their cousin, the Hopping Vampire, due to their larger number they can cause a massive energy shortage.
- They can still be massively dangerous because as soon as all energy is taken, there is very little that can be done to stop the health stealing from the Hopping Vampires who appear with them.
- Does not drop items if it suicides.