Knickknack the Clown

Knickknack the Clown was a popular urban legend in the 1950s. A popular version of the story said:
Knickknack went to the mirror maze and was never seen again. Call his name between two mirrors if you want to break his chain.

The legend became infamous in 1961, when a kid disappeared and his last photo was released:

© Eduardo Valdés-Hevia