I was playing the ne zombie map solo and stumbled upon what looked like little black lights ( I dont know how else to describe them ) but if you go down the ice slide that is located inside the lighthouse and once you get outside turn right and you will find it in a corner and if you press and hold x it will make a loud noise there are 3 others and they each have a different pitch and I think something happens if you get them in a certain order but you need 4 people to do it. I dont know if this has been found or not so please dont flame just posting what I found interesting.

[b] I encourage anyone to try this out to see what happens