S02yu-gi-oh 51: Watch

"Fool! Changing it to attack mode only makes it vulnerable, but it still has 2400 defense!"

As the white dragon dived, Yusei shouted, "I activate effect! By tributing it, I negate your monster's effect, destroying it!" The Cardian was incinerated, leaving the clone defenseless. Watch S02Yu-Gi-Oh 51

. It was a desperate move, setting up a monster designed to force a stalemate. "When it is in defense mode, you cannot

"I summon (0 ATK / 0 DEF) in defense mode!" 5D's Season 2

"Now, the effect of !" the clone sneered. "When it is in defense mode, you cannot activate card effects, and if you attack it, your monster is destroyed!" The crowd gasped. The field was paralyzed.

If you'd like to dive into the of Yu-Gi-Oh! 5D's Season 2, episode 51 (which is titled "The Fate of the Team"), I can: Tell you who actually duels in that episode. Outline the real storyline. Find where you can stream it.