Mortle, Whispering Schemer

At the beginning of each players upkeep, that
player may put a +1/+1 counter on any
number of creatures they control. If they do,
put that many +1/+1 counter on Mortle,
Whispering Schemer.
Mortle, Whispering Schemer has menace as
long as it has power 6 or greater.