Soursop is a fruit that goes by many names, including guanabana, paw-paw, sirsak, and graviola. It's the fruit of the small evergreen tropical tree native to Central and tropical South America.
Soursop fruits are large and oval-shaped, with green prickly exteriors. They can grow up to 8 inches and weigh up to 10 pounds. The flesh inside is white and fibrous.