The sugar apple (sometimes called a custard apple or sweetsop) is related to the soursop and the cherimoya. Most of them are actually green colored, but we found some really nice looking purple ones. The outer skin is relatively soft, but fairly thick, and kind of resembles a pine cone with its bumpy segmented shape. Inside, a whole bunch of small black seeds are individually encased in the creamy white flesh segments. The flesh is somewhat grainy, and tastes sweet and creamy, almost like a mild banana-mango custard. There is no real smell to the fruit itself.
More information about sugar apples: https://en.wikipedia.org/wiki/Sugar-apple