local OuterCore = Instance.new("Part",workspace)
        Core.CanCollide = false
        OuterCore.CanCollide = false
        Core.Position = Missile.Position
        OuterCore = Core.Position
        Core.BrickColor = BrickColor.new("New Yeller")
        OuterCore.BrickColor = BrickColor.new("Neon orange")
        Core.Transparency = 0.3
        OuterCore.Transparency = 0.3 

Literally no property can be assigned to the part except for parent. The error is “(property) cannot be assigned to”.This is inside a module script if that helps. Please help