JJSawry, sorry, can't remember just know they ramped up cards really quickly and then played a card which had them draw their highest cost spell and summon a minion equal to that (I think)
This sounds like a Primordial Protector, which costs 8 of itself. 7 with a Kindling Elemental played on turn one. with 1 Lighting bloom and 1 inervate or coin in hand that would make it playable on turn 4. This sets 3/4 of the specific cards (though all run doubles) of 7 drawn... Not impossible or extremely unlikely (if mulligan for those specific cards) but still quite unlikely to happen "every other game"
When it draws something like "Survival of the fitest" it summons a random 10 cost minion... yeah, those tend to be really big ;-)