Artifact
Whenever
a
creature
with
toughness
4
or
greater
is
put
into
your
graveyard
from
the
battlefield,
you
may
exile
it.
At
the
beginning
of
the
end
step,
if
three
or
more
cards
have
been
exiled
with
this
artifact,
sacrifice
it.
If
you
do,
return
those
cards
to
the
battlefield
under
their
owner's
control.
