Ariana Grande is opening up about a supernatural experience she says has had her shaken up for weeks.  In an interview with "Complex" magazine, Grande says she made the mistake of visiting a place called Stull Cemetery in Kansas City - a place rumored to be one of the seven "gates to Hell" on Earth.  In town as a part of her "Listening Sessions" tour in late August, she says she visited the cemetery with a group of friends, and took a series of photos that she claims have been haunting her through her phone ever since.  A few weeks after their visit, Ariana says she started hearing "a really loud rumble" and seeing "really disturbing images" every time she closed her eyes to sleep.  She says she then saw a "massive" cloud of "black matter" next to her bed, and watched it move around her bedroom until she fell asleep.