PETERBOROUGH, ON—Nicolette Stephenson, a 26-year-old PhD archaeology student at Trent University, took a moment out of her busy schedule of studying, teaching, and writing to send herself a text to remind her to lock the main door of the library after she left after-hours today. She then put down her phone, heard a notification one half-second later, and experienced a moment of immense excitement wondering just who had texted her.

"It all happened quite quickly, but I can try to piece together the timeline," said a flustered Stephenson. "I remember sending the text. I thought it was really important to do that, and I didn't trust myself to remember because I'm just… I've got a lot on my mind. I sent off the text, and turned back to my work."

"It was then that I heard a ding! that I've heard so many times before," she continued.

"I was nearby," says Stephenson's friend Rachael, "and she said to me, 'Did you just text me?' And I said no, of course not. Why would I text you when I'm two feet away from you? But it turned out the truth was even stranger than I imagined."

Stephenson continues the tale. "For a second, I was worried about this distraction to my work. And then I thought, hey, I've earned a break. And so I picked up my phone with, I'll admit, no small amount of anticipation. Was it Sarah getting back to me about Saturday? Was it my supervisor letting me know that my thesis was a go and getting back to me with the notes? Was it Todd finally apologizing?"

"It turned out… it was me."

Stephenson found herself in a state of shock and bemusement, to say the least. "I thought to myself, wait, but why would I… oh, of course. The lock. The key. It all fell into place. And then I thought, okay, why on earth would I not know that I had just done that? I just did it. Was I subconsciously trying to block it out? What was I trying to hide from myself? The mystery… I don't know if I'll ever truly solve it."

At press time, Stephenson was just going to shoot herself a quick email.