Charred Wand of Magic Missiles

This wand has 7 charges. you can use an action to expand 1 or more charges
to cast the MM Spell from it.
You can increase the spell slot level by one
for each additional charge you expend.
Each time you expand a charge from the wand
there is a 50% chance that nothing happens
and the charge is wasted. roll a D20 on the last
charge if its a 1 the wand burns to ash