Is it possible for something to be invisible?

Imagine you could have an invisibility cloak like that of Harry Potter. What would it look like? It would have to possess the exact same index of refraction as that of its surrounding medium. If the index of refraction of the two mediums were the same, the light rays would pass through wihtout bending at all. Using Snell's law, we discover that if the index of refraction were identical, the angle of incident and the angle of refraction would be identical as well. The following picture shows a glass rod made from pyrex placed in a solution of Karo Corn Syrup and water. Because the index of refraction of the corn syrup is higher than that of the pyrex, water is added because water's index of refraction is much lower.