Pathros's Birthing

As an additional cost to cast Pathros's Birthing, Sacrifice a creature and pay X life.
Create an X/X black legendary hydra creature
token with trample named Pathros, Primeval
Horror. X is equal to the amount of life paid to
cast Pathros's Birthing
"When the dark mage realized the extent of the Beasts
power, they realized just what they unleashed"- The Theriad