Casteliacone (ヒウンアイス Hiun Ice) is a medicinal item in Generation V, able to heal a single Pokémon's status effects. It costs 100 and is available for purchase on every Tuesday excluding the Winter months from the Casteliacone Stall on Mode Street in Castelia City.
In Pokémon Black 2 and White 2, it is available for purchase once every day. You can chose to buy one or twelve at a time. There is an Item Manic in a trailer east of Nimbasa City who will buy them for 2,000 Pen (Pokémon Yen) each, making them a highly profitable item.