You can file this under "Strangest Thing I Learned Today". It's fairly well known that James and Dolley Madison popularized ice cream by frequently serving it during their tenure in the White House. As stated on Wikipedia,
Ice cream was introduced to the United States by Quaker colonists who brought their ice cream recipes with them. Confectioners, many of whom were Europeans, sold ice cream at their shops in New York and other cities during the colonial era. Ben Franklin, George Washington, and Thomas Jefferson were known to have regularly eaten and served ice cream. First Lady Dolley Madison is also closely associated with the early history of ice cream in the United States. One respected history of ice cream states that, as the wife of U.S. President James Madison, she served ice cream at her husband's Inaugural Ball in 1813.
But, do you know what Dolley's favorite flavor was?
Wait for it.......
Yeah, that's right. Oyster.
So, a quick Google reveals that oyster ice cream is apparently popular in Japan -- big surprise there, eh? However, the version that Dolley served was probably a frozen version of the popular cream-based oyster stew with which most people are familiar.
Imagine the neapolitan possibilities.