Cuco is a bogeyman from Latin America. I couldn't find any descriptions of what it looks like, so I just had fun and hope I didn't mess it up too bad.
According to the stories it's not what it looks like that scares people, but what it does. It hides in shadows and on top of houses at night, waiting for naughty children to walk by. Said children are of course kidnapped and eaten.
It also has a female version called Cuca, but they look the same and are impossible to tell apart.