Your opponent cannot activate cards or effects during the Battle Phase while "Gaia the Dragon Champion" is in your Monster Zone.
You can activate 1 of the following effects.
● You can reveal 1 "Gaia The Fierce Knight" monster in your hand; add 1 Level 5 Dragon monster from your Deck to your hand.
● You can reveal 1 Level 5 Dragon monster in your hand; add 1 "Gaia The Fierce Knight" monster from your Deck to your hand.
You can only use this effect of "Galloping Gaia" once per turn.