Totem of Undying

This spell cannot be countered.
You cannot cast this card unless you are at 0 or
less life. If you are 0 or less life, play this card and
set your life to 1/5 of your starting life, round up.
When this effect resolves, exile it, and create an enchantment token with: during every upkeep
and end step, gain 4 life.