Skulltula

Skulltulas (スタルチュラ, Staltula) are spider-like enimies that have been featured in several Zelda games. They usually hang from the ceiling and surprise you by dropping down and attacking Link. If you go near them, they will spin around, causing you to fly away whilst getting hurt. In Ocarina of Time, this can be avoided more easily as an adult; simply fire your Hookshot at it, and the sharp hook will penetrate the skull for an instant kill. Arrows can also penetrate through the skull but sword slashes and jabs cannot. To kill a Skulltula in Ocarina of Time with a sword, the player must wait for the Skulltula turn around, exposing the soft underside. It takes two hits to kill it with the Kokiri Sword / Master Sword and one hit with the Biggoron Sword. Unfortunately, this method is not present in Majora's Mask. A special type of Skulltula that appears in Ocarina of Time is the Gold Skulltula, who drop Gold Skulltula Tokens that can be traded for useful rare items that can't be found anywhere else in the House of Skulltula in Kakariko Village. Although the Skulltula look different in each game, one constant is a skull-like shell.

In Twilight Princess, they block every one of Link's attacks until they are stunned with a shield attack, or when they attack, you jump aside and slash them. You can also defeat them by first stunning them with a Spin Attack and then finishing them off with a final blow. It's noticeable when you kill them, and when you sheath your sword, Link will sheath his sword like would when he kills a boss.

Skulltulas return in Phantom Hourglass as residents of the Ghost Ship. They look largely the same as their Ocarina of Time and Majora's Mask incarnations but are much easier to kill, requiring only a single swipe of Link's sword. However, they are much more annoying than before, since they re-spawn much faster than normal enemies and drop down from the ceiling to attack with little warning. The Cubus Sisters are deathly afraid of the spiders, cowering and screaming whenever they appear (although they might pretend to be in order to send the Reaplings after Link). They're so scared of them that the mere sight of a Skulltula causes them to freeze, hampering Link's rescue effort by forcing him to run back and offer reassurance.

In the trailer for the upcoming game Spirit Tracks, you can see Link shooting a skulltula with the cannon on his train.