Deliverance

This +1 Longbow crackles with a vindictive,
ominous energy. While holding this bow, when
you take damage, you may mark the creature that
dealt the damage for one minute. You may only
have one creature marked this way at a time. Any
attacks made with Deliverance on targets marked
this way have advantage and deal an extra 1d8
lightning damage. If you slay a marked creature,
you gain 1d10 temporary hit points. Additionally,
attacks made with Deliverance score a critical hit
on a roll of 1