Raycasting not working?

				local pos = mouse.Hit.p
				local s = (pos-tool.SmokePart.Position).Magnitude
				local laser = Instance.new("Part")
				laser.Name = "Ray"
				laser.Transparency = .75
				laser.CanCollide = false
				laser.FormFactor = "Custom"
				laser.Anchored = true
				laser.BrickColor = BrickColor.new("Really black")
				laser.Size = Vector3.new(.2,.2, s)
				laser.CFrame = CFrame.new(pos, tool.SmokePart.Position)*CFrame.new(0,0,-s/2)
				game.Workspace:FindPartOnRayWithIgnoreList(laser, {game.Workspace})
				laser.Parent = workspace
				game.Debris:AddItem(laser, .75)

The third to last line is the only error printing out "Unable to cast value to Object" can you guys help me and explain to me why this doesnt work, I have multiple versions of the second to last line but I need some help, Thank You!

• I hope this helps you

local ray = Ray.new(Vector3.new(0, 0, 0), Vector3.new(0, -1, 0)) -- Shoots down from the center of the game

local laser = Instance.new('Part')
--[[
	The laser must be a Ray not a part!
--]]

game.Workspace:FindPartOnRayWithIgnoreList(ray, {laser})

-- If you have Workspace in the table it will ignore every part in the Workspace!!

Rays

A good example

The main function you are using