Dice Roll Battle - High-Speed Riders

When an opponent's monster declares an attack: Target 1 "Speedroid" monster in your Graveyard; banish both it and 1 "Speedroid" Tuner monster in your hand, and if you do, Special Summon from your Extra Deck, 1 Synchro Monster whose Level equals the total original Levels of those 2 monsters. During your opponent's Battle Step: You can banish this card from your Graveyard, then target 1 face-up Attack Position Synchro Monster on each side of the field; make that face-up Attack Position monster your opponent controls attack that monster you control, and perform damage calculation.