Probability Field Manipulation:

The Black Cat is imbued with a genuine ability to cause "bad luck" by scientists working for the Kingpin through a bargain made with him. This power allowed her to subliminally affect probability fields, which would cause improbable, though not impossible, events of "bad luck" to occur to enemies within her line of sight. Those powers were removed from her for a while by Dr. Strange so they won't hurt those she loves, but they were restored by Mister Negative's scientist, Doc Tramma, which gave her more control over them than ever.