In minecraft there are many types of hostiles that can be found. Different hostile has different types of attacks and abilities. I will give you a link to a website that explains about it.
http://minecraft.wikia.com/wiki/Category:Hostile_Mobs

Here's the picture of one of the hostiles called Ghasts taken from http://www.pcgamer.com/previews/minecraft-halloween-update-preview-meet-the-ghasts/