D/D/D Wave High King Caesar (COTD-EN042)

2 Level 6 Fiend monsters

When a Spell/Trap Card, or monster effect, is activated that includes an effect that Special Summons a monster (Quick Effect): You can detach 1 material from this card; negate the activation, and if you do, destroy that card, then you can make 1 other "D/D" monster you control and this card gain 1800 ATK until the end of this turn. If this card is sent from the field to the GY: You can add 1 "Dark Contract" card from your Deck to your hand.

Fiend / Xyz / Effect, Code of the Duelist