Play Animation, But Go Back To Default Animation When Done Playing?

So after this script plays the animation, I want it to go back playing Roblox's character default animations, but it stays as the animation listed below. How do I make this happen? Thanks!

local animation = Instance.new('Animation')
animation.AnimationId = "http://www.roblox.com/Asset?ID=120735762"

function onEquip()
    script.Parent.Handle.UnsheathSound:Play()
end

function onActivate()
    script.Parent.Handle.SlashSound:Play()
    local player = game.Players.LocalPlayer.Character
    local animTrack = player.Humanoid:LoadAnimation(animation)
    animTrack:Play()
    script.Parent.Handle.Script.Disabled = false
end

script.Parent.Equipped:connect(onEquip)
script.Parent.Activated:connect(onActivate)