I found an event that I'm not sure has ever been mentioned anywhere before. It's on the little balcony off the train room in the Apartments. If you use the Stones effect, the sky will darken and a clock tower will chime, and a giant prehistoric-looking shark will float through the sky. You can't de-equip the Stones effect until it passes by. The sky will remain dark and the clock tower will keep chiming unless you leave the area and then return.
It's pretty neat:
