In regular games, it calls down a bolt of lightning that locks on to your enemies and causes a good amount of damage. If you get two of the spells you can make Thundara, a more powerful version of the spell, and if you get three, you can use Thundaga, the most powerful version of the spell. In CoM, you can combine two or three of the cards if you have them to make Thundara and Thundaga. You can use the ability Thunder Raid if you put a thunder card followed by two attack cards using L + R in a sleight.
Related ThreadsThunder Punch vs Meteor Mash - last post by @ Mar 30, 2011
is jolton a good thunder pokemon - last post by @ Apr 16, 2007
what thunder pokemon are easy to catch - last post by @ Apr 12, 2007
Is there a cheat for getting a thunder stone? - last post by @ Feb 11, 2003
Thunder Fang / Thunderbolt - last post by @ Feb 17, 2008