Script broke after used twice, why?

I was creating a fireball and it's actually working fine but after it's used twice it broke like this.

local remotes = script.Parent.Remotes
local assets = game.ReplicatedStorage.FireAssets
local keyholded = false

local Tweenservice = game:GetService("TweenService")
local info = TweenInfo.new(0.5,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0)

local explosioninfo = TweenInfo.new(3.5,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0)
local damagebonus = 0

local db = false

remotes.KeyHolded.OnServerEvent:Connect(function(plr, skill)
    if skill == "Fireball" then
        if not keyholded then       
            keyholded = true    

        local char = plr.Character
        local humrp = char.HumanoidRootPart
        local magiccircle = assets.MagicCircle.Q

        local base = assets.MagicCircle.Q.Center:Clone()
        base.CFrame = humrp.CFrame
            base.Parent = humrp

        local base2 = assets.MagicCircle.Q.Center2:Clone()
        base.CFrame = humrp.CFrame
            base2.Parent = humrp

        local base3 = assets.MagicCircle.Q.Center3:Clone()
        base.CFrame = humrp.CFrame
            base3.Parent = humrp

        local weld = Instance.new("ManualWeld")
        weld.Part0 = base
        weld.Part1 = humrp
        weld.C1 = CFrame.new(1,1,-2)
        weld.Parent = base

        local weld2 = Instance.new("ManualWeld")
        weld2.Part0 = base2
        weld2.Part1 = humrp
        weld2.C1 = CFrame.new(1,1,-3)
        weld2.Parent = base2

        local weld3 = Instance.new("ManualWeld")
        weld3.Part0 = base3
        weld3.Part1 = humrp
        weld3.C1 = CFrame.new(1,1,-4)
        weld3.Parent = base3

        local castsound = script.Parent.Sounds.cast:Clone()
        castsound.Parent = plr.Character.HumanoidRootPart
        castsound:Play()

        Tweenservice:Create(base,info,{Size = Vector3.new(8.223, 8.54, 0.05)}):Play()   
        Tweenservice:Create(base2,info,{Size = Vector3.new(6.008, 6.145, 0.05)}):Play() 
            Tweenservice:Create(base3,info,{Size = Vector3.new(3.613, 3.791, 0.05)}):Play()

            while keyholded == true do
                wait(1)
                damagebonus = damagebonus + 25
            end

        wait(1.5)
        castsound:Destroy()
        end
    else
        keyholded = false
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Size = Vector3.new(0,0,0)}):Play()
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center2,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Size = Vector3.new(0,0,0)}):Play()
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center3,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Size = Vector3.new(0,0,0)}):Play()
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center.PointLight,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Brightness = 0}):Play()
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center2.PointLight,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Brightness = 0}):Play()
        Tweenservice:Create(plr.Character.HumanoidRootPart.Center3.PointLight,TweenInfo.new(1,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Brightness = 0}):Play()
    end
end)

remotes.FireRemote.OnServerEvent:Connect(function(plr, skill)
    if skill == "Fireball" then
        local char = plr.Character
        local newblast = assets.QMove.FireQ:Clone()
        newblast.CFrame = plr.Character.HumanoidRootPart.Center3.CFrame * CFrame.new(0,0,-4)

        local bv = Instance.new("BodyVelocity", newblast)
        bv.MaxForce = Vector3.new(math.huge,math.huge,math.huge)
        bv.Velocity = (char.HumanoidRootPart.CFrame.lookVector * 80)

        newblast.Parent = plr.Character.HumanoidRootPart

        local name = Instance.new("StringValue",newblast)
        name.Name = "Owner"
        name.Value = plr.Name

        local shootsound = script.Parent.Sounds.shoot:Clone()
        shootsound.Parent = plr.Character.HumanoidRootPart
        shootsound:Play()

        newblast.Touched:Connect(function(hit)
            if hit ~= nil then
                if hit.Name ~= "wave" and hit.Name ~= "explosion" and hit.Name ~= "Center" and hit.Name ~= "Center2" and hit.Name ~= "Center3" and hit.Name ~= "epic" then
                    if not db then
                        db = true

                        newblast.Anchored = true
                        newblast.ba.Enabled = false
                        newblast.w.Enabled = false

                        local e1 = assets.QMove.ontouch.explosion:Clone()
                        e1.Parent = workspace
                        e1.CFrame = newblast.CFrame
                        local e2 = assets.QMove.ontouch.wave:Clone()
                        e2.Parent = workspace
                        e2.CFrame = newblast.CFrame
                        local e3 = assets.QMove.ontouch.epic:Clone()
                        e3.Parent = workspace
                        e3.CFrame = newblast.CFrame

                        local explosionsound = script.Parent.Sounds.hit:Clone()
                        explosionsound.Parent = e1
                        explosionsound:Play()

                        Tweenservice:Create(e1,explosioninfo,{Size = Vector3.new(77.983, 77.983, 77.983),Transparency = 1}):Play()
                        Tweenservice:Create(e2,explosioninfo,{Size = Vector3.new(144.179, 7.357, 141.394), Transparency = 1}):Play()
                        Tweenservice:Create(e3,explosioninfo,{Size = Vector3.new(112.292, 82.969, 105.335), Transparency = 1}):Play()

                        for i, v in pairs(workspace:GetChildren()) do
                            if v ~= workspace:FindFirstChild(newblast:FindFirstChild("Owner").Value) then
                                if v:FindFirstChild("HumanoidRootPart") and v:FindFirstChildOfClass("Humanoid") then
                                    local hum = v:FindFirstChildOfClass("Humanoid")
                                    local humrp = v:FindFirstChild("HumanoidRootPart")
                                    if hum.Health > 0 then
                                        if (newblast.Position - humrp.Position).magnitude < 20 then
                                            hum:TakeDamage(800 + damagebonus)
                                            damagebonus = 0
                                        end
                                    end
                                end
                            end
                        end

                        e1.explode1.Enabled = true
                        e1.explode2.Enabled = true
                        e1.explode3.Enabled = true
                        e1.explode4.Enabled = true
                        wait(0.5)
                        e1.explode1.Enabled = false
                        e1.explode2.Enabled = false
                        e1.explode3.Enabled = false
                        e1.explode4.Enabled = false

                        wait(1)
                        local smoke = assets.QMove.ontouch.Smoke:Clone()
                        smoke.Parent = workspace
                        smoke.CFrame = e1.CFrame
                        newblast.ba.Enabled = false
                        newblast.w.Enabled = false
                        db = false

                        local smokesound = script.Parent.Sounds.smoke:Clone()
                        smokesound.Parent = smoke
                        smokesound:Play()

                        Tweenservice:Create(smoke,TweenInfo.new(2.5,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Size = Vector3.new(91.99, 77.722, 94.663)}):Play()
                        wait(0.5)
                        Tweenservice:Create(smoke,TweenInfo.new(0.5,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false,0),{Transparency = 1}):Play()
                        wait(2)
                        plr.Character.HumanoidRootPart:FindFirstChild("Center"):Destroy()
                        plr.Character.HumanoidRootPart:FindFirstChild("Center2"):Destroy()
                        plr.Character.HumanoidRootPart:FindFirstChild("Center3"):Destroy()
                        wait(1)
                        e1:Destroy()
                        e2:Destroy()
                        e3:Destroy()
                        smoke:Destroy()
                        newblast:Destroy()
                    end
                end
            end
        end)
    end
end)