The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
The Spiderling, or Spiderlings, is a small group of Spiders that live in Dol-Guldur's Forest and Mirkwood Forest. They were either Goblin units or enemies by themselves which look like a smaller version of Shelob.
In The Lord of the Rings: The Battle for Middle-earth II, these spiders can be used at a Spider pit. It can get Banner Carriers at a Treasure Trove and Get Venom Sacks at a Level.3 Spider pit. Not only that but there's a Power of Summoning Spiderling Horde Allies only by the Goblins by 10 Power points.