You are asking questions Jurassic World Dominion,well. This will be my answer: That monster is Corrupted Marionette who created Corrupted Springtrap because The corrupted Animatronics. You saw all animatronics,yes? Well all souls of the missing children are inside Animatronics by possessing them. The souls of missing children has no body only souls. All thanks to William Afton who murdered Gabriel,Susie,Charlie,Fritz and Jeremy.