What is this fruit?

Rubus illecebrosus is a red-fruited species of Rubus that originally came from Japan. Common names include balloon berry and strawberry raspberry. It has become sparingly naturalized in scattered locations in Canada, the United States, and South America. Fruits are also unusually large for the genus, each oblong, red, up to 2 cm (3⁄4 in) long with 50–100 drupelets