evil spirit (that possesses someone); demon; devil
つき物は人に災いをもたらす。
Evil spirits bring disaster to people.
彼はつき物に取り憑かれ、奇行が続いた。
He was possessed by an evil spirit, and his strange behavior continued.
孫の癇癪が、つき物が落ちたようにぴたりと止まった。
My grandchild's tantrum stopped abruptly, as if an evil spirit had left him.