TM21 teaches a move to a compatible Pokémon. TM21 is:
Sorry, we don't have location data just yet.
|Black 2/White 2||Coming soon|
|The less the user likes you, the more powerful this move.|
|Emerald||This attack move grows more powerful the less the user likes its TRAINER.|
|A full-power attack that grows more powerful the less the user likes its Trainer.|