Interdimensional Dragon, History-vision Dragon

-Opponent Turn's Guard Step-[Discard a card with [Heal] from your hand], and call this card to your from face down. :When this unit is put on , [discard one or more cards with the sum of their grades being 3 or greater from your hand], and this unit gets +20000 until end of that battle. If you discarded cards with the sum of their grades being 6 or greater for this cost, 1, choose one of your units, and it cannot be hit until end of that battle.