Number 8: Heraldic King Genom-Heritage (BLMM-EN152)

2 Level 4 "Heraldic Beast" monsters
Once per turn: You can target 1 face-up Xyz Monster your opponent controls; this card's name and original ATK become that monster's name and current ATK, and this card's effect becomes that monster's original effect, then that monster's ATK becomes 0 and its effects are negated. These changes last until the End Phase.