Water is cool, but how much cooler would it be if we replaced it with sand? Rivers, lakes, whirlpools, even whole oceans of sand that behave more or less exactly like a body of water are common in desert settings. Bonus points if there are ships that sail said sandy seas (say that ten times really fast). You will even often find native life swimming in (or above) these seas, with everything from Sand Guppies to full-blown Sand Worms. In a broader sense, this can also apply to when anything solid or semi-solid is treated like water. For instance, while swimming in a pool of coins.