Originally used for a quest that was part of the quest chain for the Dungeon 2 set. It can no longer be acquired due to the removal of all the Old Azeroth dungeon set quests. However, players who did the quest prior to its removal and didn't destroy it afterwards are still able to use it to challenge Theldren and his cronies. This is the only means of "summoning" Arena Spoils (object).
Arena Spoils has the following loot table (WoWDB currently does not have an object page for the spoils; should be fixed soon):