how rare is a pikachu pokemon card - (58/102) Secret Rare Card Type Pikachu - Holofoil Black and

Since theres only a 1-in-7 chance of pulling a mythic rare in the normal rare slot and there are 30 packs in one box theres potential for about 4 mythic rare cards in a box

#8 Invasion of Tarkir March Of The Machine Invasion of Tarkir is one of the Mythic Rare Battle cards in March of the Machine

2021-03-19 You are never forced to activate mana abilities to pay costs, so if there is a mandatory additional mana cost (such as from Thalia, Guardian of Thraben), you can decline to activate mana abilities to pay for it and hence fail to cast the suspended card, leaving it in exile

If this is just the creature you had to sacrifice thats fine, but this can often be the creature you discarded