Poralia rufescens
Very little is known about this jellyfish, except that it lives in deep waters. It was previously spotted in the Atlantic Ocean at Lost City, and in the Pacific Ocean off the coast of Washington State and Canada at OOI RCA underwater observatory sites.
It is a flat disc, with eight tentacles in the center, and thin, wispy appendages around the outside of the disk. When it moves, it can undulate from flat to dome-shaped. It is red or pink in color, sometimes appearing brown from a distance.
References:
Marine Life Field Guide (Neptune Canada)
https://en.wikipedia.org/wiki/Poralia
http://oceanexplorer.noaa.gov/explorations/05lostcity/logs/july27/july27.html
http://species-identification.org/species.php?species_group=zsao&id=2438