Why its error:attempt an index nil with 'Transperency'?

local CharacterName = "Xapelize" -- Set this to the player name you want to hide

game:GetService("Players").PlayerAdded:Connect(function(player)
    player.CharacterAppearanceLoaded:Connect(function(character)
        wait(0.5) -- Some debug
        if character.Name == CharacterName then -- Detect if it's the PlayerName
            for _, DetectingPart in pairs(game.Workspace:WaitForChild("Xapelize"):GetChildren()) do -- Get everything on your character
                if DetectingPart:IsA("Accessory") then -- If it's accessory
                    DetectingPart.Parent = game:GetService("ServerStorage") -- Set the parent to ServerStorage (stores accessory inside it so you can get it back anytime)
                    print(DetectingPart.Name .." is an accessory")
                elseif DetectingPart:IsA("MeshPart") or DetectingPart:IsA("Part") then -- The reason why is there part is because Head is a Part
                    DetectingPart.Transparency = 1 -- Hide it
                    print(DetectingPart.Name .." is a mesh part")
                else -- Neither Accessory nor MeshPart nor Part
                    print(DetectingPart.Name .." is neither accessory nor mesh part, it's a ".. DetectingPart.ClassName) -- Print some stuff
                end

                if DetectingPart:IsA("Part") and DetectingPart.Name == "Head" then -- If the DetectingPart is head
                    for _, DetectingChildrenHead in pairs(DetectingPart:GetChildren()) do -- Get the children of Head
                        if DetectingChildrenHead:IsA("Decal") then -- If it's a decal (face)
                            DetectingChildrenHead.Transparency = 1 -- Hide face
                        end
                    end
                end
            end

            print("Character".. CharacterName .." is invisible")
        else
            print(player.Name .." is not ".. CharacterName)
        end
    end)
end)