Mirrors have long been associated with the otherworldly in superstition, folklore, and literature.
To be fair, many of them are recent inventions, stories spun in order to shock and delight in the same way the urban legends we told each other as children were in that sense, they’re not steeped in lore or grounded in reality.
Many of us grew up shutting ourselves in the bathroom with the lights off during sleepovers and chanting the name “Bloody Mary” into the mirror 13 times - but there’s a whole host of creepy mirror games out there that our pre-adolescent selves never even dreamed might exist.