This comic got me thinking. I can't recall ever tailoring encounters to my PCs' races. I'm imagining stuff like a low-lying miasma that only affects halflings or gnomes, magical sleep-based encounters designed to give elf characters the spotlight, or silly stuff like fly swarms designed to distract grippli characters. Have you guys ever used this kind of race-based encounter design in your games? Do you think it's fair ball, or is it going to make some players feel picked on?