>>50601229JP they’re called むげんポケモン (Mugen Pokemon), which can refer to either 無限 (infinity) or 夢幻 (dream/illusion).
It’s basically supposed to be the latter definition, given that they’re encountered in the dreamyard, their ORAS themes are “soaring dreams/illusion”, their power in the anime is literally called dream-casting in Japanese, they have a placard talking about dreams and memories, and so on. Localization took the former (infinity) instead and used “Eon” as a shorthand as it means a very long time- it’s not the Gnostic concept of Aeons at all anyway, that’s something Bulbapedia guessed off of the classification. This wouldn’t be the last time TPC localized “mugen” as referring to eternal time anyway- “Mugendaina” became “Eternatus” in SWSH.
