Once an action card is played and its ability resolves, the card is discarded
Upon entering the battlefield, its controller has the option of having it fight a creature, making it effectively function as removal, or it can enter with twice the number of +1/+1 counters, making it a flexible hydra that can supply a great deal of value
: Until end of turn, target noncreature artifact you control becomes an artifact creature and gains flying
Note that theres very little of value to tutor up with Primeval Titan (just Adventurer's Inn, Eden, Seat of the Sanctum, and The Gold Saucer)
After a few turns, if JTMS is not answered, it pretty much takes over the game on his way to an ultimate
Thundermaw Hellkite by Svetlin Velinov Thundermaw Hellkite | Illustration by Svetlin Velinov There are hundreds of ways to draw an awesome and impressive dragon, but if I had to choose one as the best, Thundermaw Hellkite is it