Put a PointLight called Lighting in the part. Put a BodyVelocity in the part. Put this code in a ServerScript inside the BodyVelocity.

local FallTime = math.random(100, 300)
local a = math.random(0,15)
local b = math.random(0,15)
local c = math.random(0,15)
while true do
	math.randomseed(tick())
	script.Parent.Velocity = Vector3.new(b, a, c)
	wait(1)
end
math.randomseed(tick())
wait(FallTime)
		script.Parent.Velocity = Vector3.new(b, 0, c)
		script.Parent.Parent.Lighting:Destroy() --Destroy the PointLight