Here is an amazing idea: a candle wax vase, made of blown glass. So far, nothing too amazing, but the thing is that as the candle melts, the wax falls into the vase, filling it and forming an image (which reminds me of those sand drawings). Another great thing about it, is that when the vase is full, you can send it back to the designers and they will send you a new one!
It's a bit expensive, but think of this product as 3 in 1: vase, candle holder and artwork! And as they are hand-blown, one will always be different from another. Definitely in love!