The Crimson Butterfly

At the beginning of your upkeep, if your life
is less then you started with put one shield
counter on target creature you control with
toughness less than The Crimson Butterfly
{1}, sacrifice this card: target creature or
enchantment you control gains protection
from the color of your choice until end of turn
"You have to know gentleness to feel pain, just as you
only notice the darkness if you have the sun."