Why does my script crash every time I test it out?

I have a script that creates a "ghost" of the character. It's kinda like a very short trail that is the player. Whenever I run it, it crashes. Why?

game.Players.PlayerAdded:Connect(function(plr)
    plr.CharacterAdded:Connect(function(char)
        while true do
        wait(.1)
        local getd = char:GetDescendants()
        if char:FindFirstChild("Folder") then
            char.Folder:Destroy()
        end
        for i,v in pairs(getd) do
            if v.ClassName == "UnionOperation" or v.ClassName == "Part" then
                if v.Name ~= "Torso" or v.Name ~= "Middle" then
                    local folder = Instance.new("Folder")
                    local clone = v:Clone()
                    folder.Parent = char
                    folder.Name = "Folder"
                    clone.Parent = folder
                    clone.CanCollide = false
                    clone.Anchored = true
                    if clone.Name ~= "Head" then
                        clone:ClearAllChildren()
                    end
                    clone.Name = "Ghost"
                    if v.Name == "HumanoidRootPart" then
                        v.BrickColor = char.Torso.BrickColor
                    end
                    if v:FindFirstChild("Weld") then
                        v.Weld:Destroy()
                    end
                end
            end
        end
        end
    end)
end)