Lachryphagy

When this card enters the battlefield, attach
it to a creature.
This creature has "This creature gets +0/-1
for every +1/+1 counter on it". Whenever
this creature attacks, after blockers are declared, you may put +1/+1 counters on it equal to half it's power, rounded up. If you
do, it's total power is 0 until end of turn.
"The Corinthian sends his greetings"