Last year I was in Mexico and I bought the creepiest mask I could find from a street vendor. Today I learned about The Momo Challenge. I knew it looked familiar... :
Top 21 Scariest Horror Movie Masks | Den of Geek
Scariest Mask EVER - Official TF2 Wiki | Official Team Fortress Wiki
How the 'Purge' team created its terrifying masks
The Best and Creepiest Movie Masks – Creativity, Cats & Moving Pictures
The Best Scary Masks for Halloween - Spirit Halloween Blog
10 Utterly Creepy Historical Masks - Listverse
The Town and the Twelve Creepiest Masks in Movie History - Slideshow - Vulture
5 Creepy & Unsettling Masks From History - YouTube