Stalker: Call of Pripyat → Quests → Hunt for the Chimera
An SPSA-14 shotgun and direct you to Zveroboy for the reward money. Reporting the mission to him will net you 2,000 rubles.
Gonta, having learned of Danila and Glukhar's deaths, will ask us to help him hunt the chimera. If we decide to do this, we need to meet at 3 AM. Then head to the Emerald, catch the sleeping chimera off guard, and kill it. The chimera is somehow odd; it barely resists even at maximum fire.
See also:
Pirate Invasion. Terraria event