I wound up not leaving the lantern on, but hid my FM 6P 1x18650 with 1S Q3 5A under the covers. In the wee hours of the morning, I woke up terrified that there was something in the room, but I couldn't move to hit the forward clicky. It must have been sleep paralysis. After the third or fourth try, I remembered this thread, and a split-second later, was able to turn the light on.
What's the lesson here? Whether ghosts exist or do not exist, the power of suggestion plus reading about them before bed when tired, can make for an interesting experience.