At some point in the mid-2000s, the world decided that the scariest thing on Earth were dead Japanese girls with straight black hair. The horror genre was, for a time, dominated by two of them: Sadako and Kayako. Sadako is the girl from The Ring, who kills you if you watch her video tape (they really should have made it so that she kills you if you forgot to rewind it). Kayako is the ghost of a young mother from The Grudge, who kills you for moving into her house even though rent in Tokyo is crazy and English teachers have to live somewhere. Her son Toshio is also in the house, but is a bit chattier.

Sources: Tom Holland's Terror Time