Rapana isn't native to the Black Sea at all — it arrived from the Pacific in ship ballast water decades ago and only became a local delicacy after it took over the seabed.
The meaty foot of the rapana whelk is sliced, breaded or brushed with garlic butter, and grilled or pan-fried until tender. Varna's fish markets and seafront grills sell it as a specialty rarely found away from the coast.