Countries with folk tales about a bogeyman-like creature known as the "coco, cuco, cuca, cucu or cucuy"

The Coco is a mythical ghost-monster, equivalent to the bogeyman, from Iberia & Latin America. Parents invoke it as a way of discouraging their children from misbehaving.

It is not the way the Coco looks but what it does that scares most. It is a child eater and a kidnapper; it may immediately devour the child, leaving no trace, or it may spirit the child away to a place of no return, but it only does this to disobedient children.

The oldest known rhyme about the Coco, which originated in the 17th century, is in the Auto de los desposorios de la Virgen by Juan Caxés:

Duérmete niño, duérmete ya...
Que viene el Coco y te comerá.

Sleep child, sleep now...
Else Coco comes and will eat you.

In Brazil, the Coco appears as a humanoid female alligator called Cuca. She is dressed like a woman with ugly hair and a sack on her back. Some say that she is an allusion to Coca, a dragon from the folklore of Portugal and Galicia.

You might know her from the memes

Traditionally in Portugal, however, the coco is represented by an iron pan with holes, to represent a face, with a light inside; or by a vegetable lantern carved from a pumpkin with two eyes and a mouth, which is left in dark places with a light inside to scare people.