Peperone papaccella, also listed as papaccelle riccie, is a small, round-bellied pepper grown in Campania. Across the region it answers to papaccelle, paprecchie or pupaccelle: compact fruit with a globose shape that Regione Campania treats as a highly characteristic ingredient in numerous typical recipes. That combination of form and kitchen role is why the name is worth lingering over rather than filing among generic peppers.
Craft here is as much about keeping as about cooking. Some ecotypes run more or less hot, and those fruits are used so they can be put up under vinegar. The same peppers also appear fresh or already conserved, then served as a contorno: a sharp, pickled contrast beside other dishes, or a milder, still-crisp companion when they have not gone into the jar. Heat, acidity and that squat shape do the narrative work; nothing extra needs inventing.
A useful distinction follows from the Campania account: papaccella is not only a summer vegetable on the plate but an ingredient meant to travel through the year as a preserved side. If you meet the names papaccelle, paprecchie or pupaccelle on a menu or a label, look for that globose little pepper and ask whether it is fresh or under vinegar—the recipes that make it typical sit on both sides of that choice.