The combination of incredible and terrifying.
Or a more interesting way to say incredibly terrifying.
Person 1: Omg hes such a jerk. He climbed into my window when i was sleeping, stole my ex-boyfriend's penis ring, chugged a whole gallon of milk...then left!
Person 2: Wow thats quite incredifying.
Person 1: Pardon?
Person 2: Thats incredible what he did and its terrifying he broke in and stole someone else's penis ring!