Arcbound Hydra

Modular X (This enters the battlefield with X +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
{x}, {t}: Put X +1/+1 counters on Arcbound
Hydra.
When Arcbound Hydra dies, if you control no
other artifact creatures, it deals damage to you
equal to the number of +1/+1 counters on it.