From afar, one might think that the windows in the Slytherin Common Room just haven't been washed in twenty years. But when you get closer or look harder, you might see a fish flash before your eyes. Or maybe a kelpie. Or perhaps a tentacle of the Giant Squid.

The Slytherin Common Room resides in the Dungeons of Hogwarts, meaning they are underground. What else is underground, you may ask? Why, the Lake, of course. These windows give you a marvelous view of the Black Lake. Most creatures in the lake tend to like their privacy, so you won't see them all the time, but you can usually see quite a few mindless fish and other things swimming around. Just don't go tapping on the glass. You never know what might pop up to tap back.