Artifact
:
Add
.
At
the
beginning
of
each
player's
upkeep,
that
player
may
put
a
doom
counter
on
this
artifact
or
remove
a
doom
counter
from
it.
Then
if
it
has
three
or
more
doom
counters
on
it,
sacrifice
this
artifact.
When
you
do,
it
deals
6
damage
to
each
creature.