Number 1: Infection Buzz King

2+ Level 8 monsters
Once per turn, during your Standby Phase: You can attach 1 card from your opponent's GY to this card as material. You can only use each of the following effects of "Number 1: Infection Buzz King" once per turn. If this card is Xyz Summoned: You can look at your opponent's Extra Deck and send 1 card from it to the GY. You can detach 1 material from this card, then target 1 card your opponent controls; destroy it, then, if you destroyed a face-up monster, inflict damage to your opponent equal to half the ATK that monster had on the field.