To attach a Lightning Energy card from your hand to Raikou, you must discard an Energy card attached to Raikou. (Attach the Lightning Energy, and then discard an Energy card from Raikou.)

Lightning Sphere

40+

You may flip a coin. If heads, discard all Lightning Energy cards attached to Raikou. This attack does 40 damage plus 20 more damage for each Energy card discarded in this way.