Read this:
http://creepypasta.wikia.com/wiki/Gengar_and_Clefable
Now look at their typings. One of normal-type, and the other has ghost-type. Due to their immunities, neither of them could hit the other with STAB attacks, since they'd just be immune to each other.
Have you ever tried to hit your shadow?
There's a lot of creepypasts shit on here thats all been extenisvely researched.
The Lavender Town Syndrome (also known as "Lavender Town Tone" or "Lavender Town Suicides") was a peak in suicides and illness of children between the ages of 7-12 shortly after the release of Pokémon Red and Green in Japan, back in February 27, 1996.