See a sneak peek for the next The Vampire Diaries episode “We All Go a Little Mad Sometimes,” as well as a promo containing new footage.

In “We All Go a Little Mad Sometimes,” Elena is plagued by terrifying hallucinations after killing Connor, the Hunter who was a member of the legendary group called The Five. Unknowingly, Elena severed the link that would lead to a cure for vampirism, but when Connor died, his powers seemed to transfer to Jeremy.

Plus, with another Hunter coming to Mystic Falls soon, there’ll be plenty of opportunities for Klaus and Stefan to find the cure for her. Only question is: will Elena still want it then?

In the following sneak peek, we see a scene featuring Damon and Stefan arguing about the cure, and a phone call with Klaus reveals that he knows about the hallucinations:

In the extended promo, we learn a bit more: “When one kills a Hunter, there is a bit of a consequence,” Klaus reveals to Stefan, and we see more scenes of Elena, scared of Damon and Stefan – and then Katherine arrives:

Is Katherine really there, or is it another hallucination?! We can’t wait to find out.

The Vampire Diaries 4×06 “We All Go a Little Mad Sometimes” airs Thursday at 8/7c on The CW!