SOS, American Military (originally) slang for Creamed Beef on Toast was just a nickname, drawn from the idea of some mystery sauce on a slab of toast.

Properly made, it can be tasty, although like other local delicacies it IS an acquired taste.

Old time military types would go down the chow line getting eggs, home-fries (chunked up bits of previously cooked potatoes that have been refried), toast, grits (in the south), and the beef-in-gravy over the lot.

Sort of binds everything together.

Dave