If you were dreaming that a baby cracked their skull, it might mean bad news. The dream imagery of baby means a new person or a new project. The dream event of cracking skull can mean wounding or damaging, even at such a young age and stage. If you had been working with a person in your waking life, this dream warns you that person “cracked their skull”, or in other words, became ill/ unable to perform.
If you had been working on a project, this dream may imply the project is spoiled. The damage may show up later as a problem or failure to do as it was fashioned to perform.