A lot of jellyfish are lookers. The flower hat jelly has hot pink lures curling from its bell. The orange Pacific sea nettle is radiant as a star. But jellyfish are even more beautiful in multitudes than on their own -- scientists and tourists alike rave about snorkeling through the masses in the so-called “Jellyfish Lake,” on the Pacific island of Palau. (The golden jellies’ sting isn’t perceptible to swimmers, which makes them even prettier.) Perhaps the most beautiful of all are the common moon jellyfish. Their simple, pale, pulsing forms are almost ethereal.