All of my starfish have been out of water. They do need to be acclimated slowly though. I think you may be thinking of sponges. They are not supposed to be exposed to air as they will get air in their "cells" and can't expel it.
Speaking of acclimating things, several years ago I ordered some serpent stars, shrimp, crabs, and snails. My acclimation plan was to use two shoebox size plastic pans (one for each tank) and put them in these with the shipping water and float them. Every fifteen minutes I planned to add a cup of tank water to the pan. I put all the critters in the pans. I floated the first one in one tank and took the other one to the other tank and put it in. Then I went back and looked at the first one. The powerheads on a wavemaker came on and swamped the pan and dumped all the critters out. I ran back in the other room and secured that pan with the glass top so it couldn't turn over. I acclimated them according to my schedule and then released them. I figured that the ones that got dumped would die. Everything lived. Go figure.