>>21509016There were the Holon cards which did the same thing as "Dark" Pokemon, except that they were half Steel (or Metal in the TCG.) You could build a whole Holon deck due to the support of trainer cards and stuff. It was odd because there were even Pokemon with changed types (for example, Latios being a Water type.) I think they stopped the type mix ups after the Holon series though.
Kinda wish the changed type thing was worked into a spin-off Pokemon game - possibly even set in the Holon region.