Yup, surprise lily for sure. They make those long, strap like leaves in the spring and then the whole thing just disappears. (You never really even see shrivelled leaves lying around, just poof, gone.) Then there is no sign of the plant for at least three months. Then after you have completely forgotten it used to be there, all of a sudden the flower spike pops up. And it goes from poking out of the ground to 18" tall and in full bloom almost overnight (well in about four days anyway). No wonder another one of its names is magic lily!