Ocarina of Time
They are small spider like enemies and their back is shaped like a skull. Skulltula are found in many of the dungeons when you are a kid, and there are a few as an adult. They also have an entire side quest dedicated to them were you hunt down the gold skulltula to free all the people that live in the House of Skulltula that were cursed and turned into half human half Skulltulas. When you kill the golden skulltulas and collect their token you will receive an item. You will receive these at 10 20 30 40 50 and 100 tokens total. First you will get the adult wallet(can carry 200 rupees.) Next you will receive the Stone of Agony(controller will vibrate when near gold skulltulas.) The third prize is the Giants wallet(can carry 500 rupees.) The fourth reward is Bombchus. At 50 you will get a heart piece. Finally at 100 you can get an unlimited amount of rupees. A guide for the golden skulltula can be found here: http://www.zeldadungeon.net/Zelda05-ocarina-of-time-gold-skulltulas.php
Skulltula appear very much like their Twilight Princess predecessors. They are spider-like creatures with eight legs whos main attack is to dash its body towards Link. Skulltulas will appear in several different ways. Some just drop down the cieling, others are hanging from a string, while some have full blown spider webs created to block your path. Link can knock down skulltulas by breaking the string or spider web utilizing the beetle.
Once a skulltula is on the ground, use your sword techniques to harm it. Once you've sliced it with a sword attack the skulltula will stand on its back legs, revealing its weak spot. Slash at the large purple jewel on its stomach to defeat the skulltula. In some cases, after hitting the skulltula a number of times, it will flip over and land on its back. At this point Link can jump and deliver a finishing blow, stabbing right through its weak point.