Local script runs script.parent before pressing the assigned key to it, how can I fix that?

I have been trying to create a script where if the key V is pressed a part spawns on the humanoid leg and makes him trip, but I can't get that to work using Instance.new

local Player = game:GetService("Players").LocalPlayer
local Mouse = Player:GetMouse()

Mouse.KeyDown:Connect(function(Key)
	Key = Key:lower()

	if Key == 'v' then
		local part = Instance.new("Part")
		part.Name = "Test"
		part.Anchored = true
		part.Position = Vector3.new(10,15,0)
		part.Parent = game.Workspace
		part.CFrame = 	CFrame.new(Player.Character.UpperTorso.Position.x,Player.Character.UpperTorso.Position.y-	3,Player.Character.UpperTorso.Position.z)
		part.Transparency = 1
		part.Size = Vector3.new(5,0,5)
		part.CanCollide = true
	end
end)


script.Parent = workspace.Test

script.Parent.Touched:Connect(function(hit)
	if game.Players:GetPlayerFromCharacter(hit.Parent) then
		hit.Parent.Humanoid.Sit = true
	end
end)

I get the error message " Test is not a valid member of Workspace " even before pressing the key V