Ghosts (Danny Phantom)

Ghosts are supernatural creatures that appear in the Nickelodeon television series Danny Phantom. In some cases, they are said to be the embodiments of those who passed from the living world. However, Butch Hartman confirmed that ghosts were actually monsters from another mention and they only have those tragic backstories to have a connection to the human world. Some ghosts are wrathful and malevolent beings who enjoy tormenting those who live in the human world, such as Skulker, Ember McLain, or Penelope Spectra. Several other ghosts, however, are quite benevolent and friendly with Team Phantom, such as Clockwork, Pandora and Frostbite. 
They are capable of having children with each other, as in the alternate timeline in "The Ultimate Enemy", Box Ghost and the Lunch Lady Ghost we're married and had a child named box lunch. It is unknown if full-ghosts can have children with half-ghosts, but it is possible.
A half-ghost are Human/ghost hybrids that can come to be when a human is exposed to ectoplasmic energy that mixes with their human DNA, sometimes called a "Halfa."