Husk cherries. 

They look like small cherry tomatoes wrapped in a tomatillo husk - the seller from Alewife Farm at Tucker Square Greenmarket this morning told me they're related to tomatillos. Physalis pruinosa is the plant name - and they can also be called "strawberry tomatoes," "ground tomatoes," "ground cherries," or "winter cherries." We found once we squeezed the little orange sphere out of it's paper lantern husk - it's delicious. Not sure they what we'll do with them aside from peel the husks off and eat them straight - they're a unique and not-too-sweet late summer snack. @thekitchn has some great suggestions for how to use them - might pop them into salsa...or pie! 
More here - The Kitchn - https://www.thekitchn.com/5-reasons-youll-want-to-buy-husk-cherries-at-the-farmers-market-tips-from-the-kitchn-205798

Smithsonian -  https://www.smithsonianmag.com/arts-culture/five-ways-to-eat-ground-cherries-98470003/#BpG2WVoj78LCro7b.99