>Did you know that there is a village called "Holon" deep in the Phantom Forest where Mew is said to live? It is a power spot filled with mysterious power, and researchers are working every day to solve its mysteries. Then, one day, the strong magnetic power generated by Holon caused changes in the Pokemon living in the area! That's right, Pokemon with different types than before began to appear. And because these Pokemon are the fourth to be discovered after "Normal", "Extra", and "Star", the researchers named them "δ-Delta" types!Google Translated text from Poké
mon.co.jp's card section for Holon Research Tower.
Has an archived image of Holon, same as the one seen in
>>56069481, but alas, the only resolution of it is tiny for modern monitors.
Source:
https://web.archive.org/web/20051212111047/http://www.pokemon.co.jp/card/index.html 