Crystalline Duelist

Whenever Crystalline Duelist deals combat damage
to a player, you may have it deal 1 damage to target creature or planeswalker that player controls.
Whenever Crystalline Duelist is dealt damage, it
gets +1/+1 until end of turn for each 1 damage it was dealt.

Their warpicks are sharper than spite, and their hearts colder than the stone they carve." -Drizzt
Do'Urden, on Duergar combat tactics.