The tentacles contain a special gland producing a ferment capable of dissolving the skin and simultaneously preventing blood from clotting. Discovering the ferment's composition could be the cornerstone of a whole series of great medical advances. Normal stalkers buy it for 1350 Ru, Skinflint buys for 2250 Ru, Sakharov buys for 3750 Ru. This item is the most valuable item when compared with its weight. So don't sell whenever you find it, wait till you get to Sakharov's base alive.