First, discard "Crystron Smiger" to Special Summon "Crystron Sulfefnir" with its own effect.

Then, destroy "Crystron Sulfefnir" with its own effect to activate its effect that triggers when it is destroyed.

With that effect, Special Summon "Crystron Citree" from your Deck and end your turn.

Now, during your opponent's Main Phase or Battle Phase, you can activate the effect of "Crystron Citree" to Special Summon "Crystron Smiger" from your Graveyard and Synchro Summon "Crystron Ametrix"!

When "Crystron Ametrix" is Synchro Summoned, all of your opponent's face-up monsters are changed to Defense Position. Use this combo to prevent your opponent from attacking!