Bloodcaller

when Bloodcaller enters the battlefield draw a card and gain 3 life.
at the beginning of your upkeep pay any amount of life, then create a X/X Demon Dragon creature named "Goriae" with blood counters equal to the amount of life payed this turn and with Trample, Flying and "this creature's power and toughness are equal to the number of Blood counters on Goriae".