In the 1888 book "Camp-fire Chats of the Civil War," C.F. Matteson, a former Union soldier from the 17th Illinois Infantry, recounted the story of a comrade named "Bob," who was gravely ill with measles in a camp in Missouri and wanted to give his last will and testament orally to him. But instead of deciding who got his personal property, Bob instead dictated the precise manner of what was expected to be his imminent burial. He wanted to be interred face down, with his head pointed eastward and a clam shell in each hand. Matteson felt compelled to ask why. The seemingly dying soldier explained to him that in the event that the angel Gabriel suddenly decided not to blow his horn and summon him to the hereafter, he wanted to be in a position where he could tunnel under the Mississippi River and come up in his home state.
Fortunately Bob — whom Matteson recalled as a bit of a joker — managed to recover from his illness, and survived combat to return to Illinois without the need to tunnel out of his grave. But the notion of a soldier or sailor making a last-minute, informal last will and testament on the battlefield or at sea — perhaps spoken, or else scribbled hastily on whatever scrap of paper was handy — actually was a thing that combatants in peril once did. There's a long tradition of countries giving military service members leeway to leave behind informal wills that courts often accepted, even though they didn't conform to the usual formalities expected of civilian wills.