Pronged Spear

Acquisition
Nightfall
 * Istan
 * Issnur Isles
 * Bladed Termite
 * Ridgeback Skale
 * Kourna
 * Arkjok Ward
 * Kournan Zealot
 * Realm of Torment
 * Domain of Anguish
 * Domain of Secrets
 * Margonite Reaper
 * Margonite Executioner
 * The Desolation
 * The Ruptured Heart
 * Margonite Executioner
 * The Sulfurous Wastes
 * Awakened Thought Leech
 * Vabbi
 * The Mirror of Lyss
 * Roaring Ether
 * Resplendent Makuun
 * Skree Raider
 * Wilderness of Bahdza
 * Rain Beetle
 * Yatendi Canyons
 * Margonite Reaper

Eye of the North Drop research is ongoing, and can be found here.
 * Depths of Tyria
 * Gunnar's Hold (Only during Fronis Irontoe's Lair)
 * Stone Summit Carver
 * Cathedral of Flames
 * Crypt Banshee
 * Crypt Ghoul
 * Servant of Murakai

Dye
Dye affects the inventory icon but has no noticeable effect on the item.