Sorcery
Put
a
+1/+1
counter
on
target
creature,
then
double
the
number
of
+1/+1
counters
on
it.
Flashback
.
This
spell
costs
less
to
cast
this
way,
where
X
is
the
greatest
mana
value
of
a
commander
you
own
on
the
battlefield
or
in
the
command
zone.
(You
may
cast
this
card
from
your
graveyard
for
its
flashback
cost.
Then
exile
it.)