Mirari

This item has 3 charges. When you cast a spell
that targets only one creature and doesn't have a
range of self, you can expend a number of
charges equal to the spell's level to target a
second creature in range with the same spell
(1 charge if the spell is a cantrip). This item
regains 1 charge daily at dawn. If you expend the
last charge, roll a d20. On a 1, the item bursts
into shards and is destroyed. Everyone within a
10-foot radius must succeed on a DC 15
Dexterity saving throw or