:SetPrimaryPartCFrame will not function?

So, Im trying to make a Octopus Tentacle that plays an attack animation when it spawns. It spawns in a different spawn each time. However, when I try to get it to work, the Tentacle does not move where it should:

local plrs = game.Players:GetChildren()
for i = 1, #plrs do
    repeat wait(1) until game.ReplicatedStorage.Texts.Value == "2:28"
    while wait(3) do
        local tentacleclone = game.ReplicatedStorage.Tentacle:Clone()
        tentacleclone.Parent = script.Parent
        local spawnpoints = script.Parent.TentacleSpawnPoints:GetChildren()
        local random = math.random(1,9)
        print(random)
        local randomspawn = script.Parent.TentacleSpawnPoints["SpawnPoint"..tostring(random)]
        print(randomspawn.Name)
        print(randomspawn.StartPart.Position)
        tentacleclone:SetPrimaryPartCFrame(CFrame.new(randomspawn.StartPart.Position))
        for _, v in pairs(tentacleclone:GetChildren()) do
            if v:IsA("MeshPart") then
                v.CFrame = CFrame.Angles(math.rad(180),math.rad(-360),math.rad(180)) --math.rad is needed for radians when using CFrame.Angles
            end
        end
        local TweenService = game:GetService("TweenService")
        repeat
            wait(.28)
            local moreHeight = tentacleclone.PrimaryPart.Position
            local currentPosition = tentacleclone.PrimaryPart.position
            local goal = {}
            goal.Position = Vector3.new(currentPosition.X,moreHeight.Y + 25,currentPosition.Z)
            local tweenInfo = TweenInfo.new(1) -- add N time
            local tween_start = TweenService:Create(tentacleclone.PrimaryPart, tweenInfo, goal)
            tween_start:Play()
        until goal.Position.Y > randomspawn.EndPart.Position.Y
        local Animation = tentacleclone.Humanoid:LoadAnimation(tentacleclone:WaitForChild("Attack"))
        Animation:Play()
        Animation.Stopped:Wait()
        repeat
            wait(.28)
            local moreHeight = tentacleclone.PrimaryPart.Position
            local currentPosition = tentacleclone.PrimaryPart.position
            local goal = {}
            goal.Position = Vector3.new(currentPosition.X,moreHeight.Y - 25,currentPosition.Z)
            local tweenInfo = TweenInfo.new(1) -- add N time
            local tween_start = TweenService:Create(tentacleclone.PrimaryPart, tweenInfo, goal)
            tween_start:Play()
        until goal.Position.Y < randomspawn.StartPart.Position.Y
        tentacleclone:Destroy()
    end
end

I believe my problem is coming from line 13. If something was unclear, please let me know. Thank you!