Ashes of Athas campaign, in original run - I played a Druid of the natural world, long-term strategic goal to end the elemental intrusion into the world and bring Nature back into its rightful balance - thereby healing the currently-ruined world. One module, everybody but me was playing a pre-gen temporary character. We found a chamber where you could sacrifice to a para-element and gain its power (changing your essential nature). One possibility was Silt, but nobody else wanted to pick it. I was SO tempted, because the silt is a defining characteristic of Athas. * Ultimately, unto mine own self was I true, and stayed a Druid of Nature's Intention.
* The description was solely fluff. Mechanically, the character's race would be changed to one or another form of Genasi. I found this out much later.