Once during your turn (before your attack), you may search your discard pile for a Basic Pokémon (excluding Pokémon-ex and Ditto) and switch it with Ditto. (Any cards attached to Ditto, damage counters, Special Conditions, and effects on it are now on the new Pokémon.) Place Ditto in the discard pile.
Energy Ball エナジーボール
Does 10 damage plus 10 more damage for each Energy attached to Ditto but not used to pay for this attack's Energy cost. You can't add more then 20 damage in this way.
In the Energy Ball's attack, than is misspelled as then.
Form Variation is similar to Transform, a move that Ditto can learn; its inability to switch with a Ditto mirrors Transform's inability to transform a Pokémon into another Ditto, an inability introduced in Generation II primarily to prevent Ditto vs. Ditto matchups from lasting forever. Energy Ball is a move in the Pokémon games introduced in Generation IV that Ditto cannot learn.