A secret and exclusive intelligence operation involved in passing word about anything going on in the unit, including general gossip. Be wary, if you break the code of the Lance Corporal Underground and snitch classified information, you will be thrown out and shunned, even if you retain the rank of Lance Corporal. There is no getting back in.

Jones got a DUI last night and all the troops knew about it before his Platoon Sergeant did, thanks to the Lance Corporal Underground.