Assault Synchron [BLMR-EN003] Secret Rare

During your Main Phase: You can Special Summon this card from your hand, then take 700 damage, also while it is face-up in the Monster Zone, you cannot Special Summon from the Extra Deck, except Synchro Monsters. If a face-up Dragon Synchro Monster(s) you control is Tributed or banished (except during the Damage Step): You can banish this card from your GY, then target 1 of those monsters; Special Summon it. You can only use each effect of "Assault Synchron" once per turn.