Quick question: Can a Ray become visble?

you could create a part and scale/position, perhaps something like this

local startingPos = --where the ray came from
local pos = --the position the ray hit

local trail = Instance.new("Part", workspace)
trail.FormFactor = "Custom"
trail.Anchored = true
trail.Locked = true
trail.CanCollide = false
local distance = (startingPos - pos).magnitude
trail.Size = Vector3.new(0.01, 0.01, distance)
trail.CFrame = CFrame.new(startingPos, pos) * CFrame.new(0, 0, -distance / 2)