You Eventually Vanish

A computerized creation gone out of control called the Clown has been terrorizing a group of aliens and members of Janeway's crew. Janeway manages to trick him by offering herself up, only to instead connect herself to the system in a way that allows the Clown to think she's on the system, but it's actually only a holographic representation. Deprived of victims, the Clown can now only fade away. As he does so, he admits to the holographic Janeway that he is himself afraid.

Example of:
Horrifying the Horror