Number 23: Lancelot, Dark Knight of the Underworld

Card text

2 Level 8 monsters This card can attack your opponent directly while it has Xyz Material. When this card inflicts battle damage to your opponent: You can target 1 face-up monster your opponent controls; destroy it. Once per turn, during either player's turn, when a Spell/Trap Card, or another monster's effect, is activated: Detach 1 Xyz Material from this card; negate the activation.