Blizzard numbers items as they are created, so the named items next to ID 37921 (37889 to 37934) were usually added in the same batch as Deadnettle: the same quest line, zone, vendor or reward set.
Retail recipes that use it: Elixir of Lightning Speed, Elixir of Mighty Thoughts, Indestructible Alchemist Stone, Lesser Flask of Toughness and Wrath Elixir.
Connected realms with a listing in the latest MoP Classic scan: EU 0 of 25, KR 0 of 5, TW 0 of 8, US 0 of 23.
Item data: Blizzard's MoP Classic Game Data API (static data 5.5.4.67732). Prices: per-unit buyouts from one Blizzard Auction House snapshot per connected realm per hour; market is the quantity-weighted median of a realm's listings. Retail column: the retail client datamine.
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