8. Toshio In The Reflection - Ju-On: The Grudge
Near the end of the original Japanese version of The Grudge, protagonist Rika (Megumi Okina) is seen caring for a pervy man suffering from dementia, Mr. Saito (Isao Yatsu).
The man seemingly plays peek-a-boo with himself while Rika wheels him around - admittedly a not particularly abnormal act for someone beset by mental deterioration.
And yet, for a few fractions of a second when the door to the hospital is opened by an orderly, the ghost of young Toshio (Yuya Ozeki) can be spotted in the door's reflection, standing right beside Saito and Rika.
As it turns out, Mr. Saito wasn't entirely out of his mind, at least not in this moment - he was playing peek-a-boo with Toshio.
Reflections are such a simple-yet-brilliant way for filmmakers to hide creepy surprises and details in plain sight, so it's honestly surprising we don't see more creative uses like this.