XX-Saber Fulhelmknight (XSPU-EN001) [X-Saber Power-Up]

When your opponent declares an attack, you can select the attacking monster, and negate the attack. You can only activate this effect once (while this card remains face-up on the field). If this card destroys a Defense Position monster your opponent controls by battle, You can select 1 Level 4 or lower "X-Saber" monster in your Graveyard, and Special Summon it.