Spider: Like skeletons, spiders are a staple in most role-playing games because, let's face it, they're creepy when they're the size of a large dog. Spiders in Minecraft make a rather disturbing rustling sound, as if you were walking across a pile of dried leaves. They can also climb mountains and other tall structures, and their ability to jump high in the air makes them difficult to target.
Spiders will appear during the day as well as at night, but daytime spiders are harmless as long as you don't provoke them. Defeating a spider will give your character string, which can be used to make bows and fishing poles.