Making A Spinning Part Above Character?

Probably a frequently asked and used question but here it is. I've welded a Part (duck) above the Character's head upon joining. But I'm unaware of how to make it spin? What I've got so far just makes it do something.... weird*?

--PlayerAdded script (ServerScriptService)

function makeDuck(plr)
    local duck = script["Blue Duck"]:clone()
    duck.Parent = plr.Character
    duck.Position = plr.Character.Head.Position + Vector3.new(0, 4, 0)
    duck.Rotation = plr.Character.Head.Rotation
    local weldTo = plr.Character.Head
    local weldToCf = weldTo.CFrame:inverse()
    local weld = Instance.new("Weld")
    weld.Name = "DuckWelding(warning, high temperatures)"
    weld.Part0 = weldTo
    weld.Part1 = duck
    weld.C0 = weldToCf
    weld.C1 = duck.CFrame:inverse()
    weld.Parent = weldTo
    duck.Anchored = false
    duck.CanCollide = false
end

And then after this:

--Script inside duck
local duck = script.Parent

function rotateSomeDuckyThatIUsedToKnow()
    local weldForDuck = duck.Parent:FindFirstChild("Head")["DuckWelding(warning, high temperatures)"]
    while wait() do
        weldForDuck.C0 = duck.CFrame:inverse()*CFrame.fromEulerAnglesXYZ(0, math.pi/180, 0)
    end --This is basically the only line that doesn't do what I want it to
end



duck.AncestryChanged:connect(function(child, parent)
    print("someDuckyThatIUsedToKnow got TRIGGERED!!!!!") wait(5)
    if parent:IsA("Model") then
        rotateSomeDuckyThatIUsedToKnow()
    end
end)

The line inside the while loop in rotateSomeDuckyThatIUsedToKnow() is basically the only part I'm ignorant of what I'm supposed to be doing. Can someone explain what's happening here? According to what I read from the wiki, it should rotate the duck.

*As I wrote this I found one thing I was doing wrong; so weird now means it is kinda moderating its position above the head as if it's some futuristic hoverboard.