Must be Special Summoned by its own effect.

You can target 4 Fusion, Synchro, Xyz, and/or Link Monsters in the GYs; Special Summon this card from your hand, and if you do, banish them.

At the start of the Damage Step, if this card battles a Special Summoned monster: Destroy all your opponent's Attack Position monsters, then inflict 800 damage to your opponent for each Fusion, Synchro, Xyz, and Link Monster destroyed by this effect.