Enchantment
Cumulative
upkeep
(At
the
beginning
of
your
upkeep,
put
an
age
counter
on
this
permanent,
then
sacrifice
it
unless
you
pay
its
upkeep
cost
for
each
age
counter
on
it.)
At
the
beginning
of
your
draw
step,
destroy
each
creature
with
mana
value
equal
to
the
number
of
age
counters
on
this
enchantment.
They
can't
be
regenerated.