One time is college I got really, really high all by myself. It was freshman year and my roommate left campus for the night. I sat on bed and smoked what the kids call grass until I reached an unsafe mental state. I was very close to finishing a joint when I noticed someone or something flash by the window. I quickly hid the joint and went to see who/what it was. It was late, I was high but was still sure I saw something. I stood up quickly and saw it again then ducked as to hide from it. Why was I hiding you ask? Because I was high. I stood back up and the same thing happened again with the same ducking result. I did this at least 4 more times before I realized that it was not a window I was looking in but rather a mirror.
Lesson: Doing drugs alone is not cool