Pokémon Stadium

[gamemaster1991]

In Pokémon Stadium, if a Pokémon knows an attack it normally shouldn't be able to, the text changes color to purple.
However, even if someone teaches a Pokémon a legitimate move through G/S/C and trades it back, if the move cannot be learned in R/B/Y, the game will still show it as purple.

For example: Teaching a Squirtle TM33 - Ice Punch. TM22 - Solar Beam.

That's pretty cool.