You want to look scary? I know there are many kinds of scary contact lenses. If you have no prescription from the doctor, you'd be careful when you try it. Many people have been infected by wearing contact lenses. Different people has different eye shape, some people may not suitable for wearing contact lenses. Moreover, contacts lenses can easily infect your eyes if you are not using it properly. So before you try this, I hope you can take the risks into consideration.
Here are two websites I have found, plenty of them!
You can buy them from costume play shops or online costume play shops.
As there are many special contact lenses made for costume play. Some of them are made for Halloween. You can even buy that from amazon.com. Just enter "scary contact lenses" on amazon.com, and you will see many odd contact lenses. For example, you can click on this link to see one of them.
Well, for scary contact lenses, I have to say that they are suitable for people who want to make them look unique and fantastic. And generally speaking, scary contact lenses are a kind of lenses which are scary with several of styles and also have different colors. For some people, it will be difficult to wear them. So in common, scary contact lenses are popular with young people. To buy them, of course, you can just go and surf the internet, and there are many online stores which can just have some choices. For example, you can buy them at http://www.youknowit.com/online-shop/scary-contact-lenses.cfm.and http://demoneyez.com/Scary. And the prices can be different, and not so expensive. Anyway, just go and have a look.