The Spiderling is a mob found in the Spider Lair. It does not have any main drops, but they have a really rare chance to drop the Purple Dye item, which usually costs 100 . Purple Dye is probably the most sought-after color of the 7 Dye variants, which pairs well with the nasty nature of Spiderlings and their lesser-use of farming due to having no other drops, making it even more of a reward if one actually manages to obtain the dye drop.
Spiderlings are to be taken seriously, as one attack can drain a large portion of health away, and normal variants are hard to hit with standard melee attacks due to their small size. Supersized Spiderlings that are spawned by the Spider Queen are even harder to kill due to their high health and high damage output. Spiderlings sometimes attack in hordes, so rallying a group of Spiderlings would potentially cost a player their life if they attempted to kill them all at once. Using a Wooden Bow or Spider Leg Bow is a very effective way for hunters to deal with these pesky monsters, although hordes of them may still be an issue.
The only way to obtain idols is from the spiderlings spawned from the Spider Queen's screeches.