The Lost Spirits of Shuma-Gorath first appeared in 2009 in Marvel Comics "Doctor Voodoo: Avenger of the Supernatural" Vol 1 #1.
They are the forged-souls of Shuma-Gorath forming an unreal abyss of pure suffering. The only way to pass through them unharmed is by creating a mystical portal as mere contact can shred a mortal's reality and are even able to damage powerful Hell Lords. They can be commanded to perform various functions, from forming a tornado-like barrier to attacking specific targets. Doctor Voodoo during his time as Sorcerer Supreme used them to guard the Scrying Stones of Chthon and to attack Nightmare, who managed to take control of them and directed them to attack the Doctor.