A sponge is a sponge because its porous material is able to absorb liquid of any kind. But what about liquid metal? Can a sponge actually absorb the heavy quicksilver material known as mercury? Not at all.
At best, a little bit of mercury goop gets caught on top of the sponge and slides away like its T-1000 shaping itself back together. [Tao Fledermaus via The Awesomer]