Helena Walker

Helena Walker enters the battlefield with
{x} 1/1 Dodo Tokens and 0/+{x} toughness.
•When one of the Dodo Tokens die, Helena Walker
untaps and gains a +2/0 until end of turn.
•{g}{u}, Helena Walker summons a tamed pteranadon
and gains flying until end of turn.
•{t}{w}{u}{g}, Create {x} Dodo Tokens where {x} is
the amount of life gained that turn.
{bull}{t}{g}{g}{u}{u}, If you sacrifice a non-human creature
spell you can cast a 5/5 Rex Token Creature.