>>55675488You could ask the same question for the localized name, they are called "eon" pokemon as in an absurdly long, incommensurable amount of time, but they really make a play with fantasy and dreams (both pronounced むげん mugen), and given their powers to see what they couldn't normally see and to turn themselves into mirages, as well as their eerie island, it's even weirder they aren't translated simply as "dream pokemon".
But hey,
every dream is another world in the infinite multiverse I guess. 