This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Cuco (Latin America)
The Coco or Coca (also known as the Cucuy, Cuco, Cuca, Cucu, Cucuí or El-Cucui) is a mythical ghost-like monster, equivalent to the bogeyman, found in Spain and Portugal. Those beliefs have also spread in many Hispanophone and Lusophone countries. It can also be considered an Iberian version of a bugbear as it is a commonly used figure of speech representing an irrational or exaggerated fear.
The Cucuy is a male being while Cuca is a female version of the mythical monster. The "monster" will come to the house of disobedient children at night and take them away. There is no general description of the cucuy, as far as facial or body descriptions, but it is stated that this shapeshifting being is extremely horrible to look at. The coco is variously described as a shapeless figure , sometimes a hairy monster, that hides in closets or under beds and eats children that misbehave when they are told to go to bed.