Staff of life and death

You have advantage on death saving throws. The
staff has 7 charges. You can use an action to
expend a number of charges and cast a spell from
the staff. Animate Dead (1 charge) and Create
Dead (5 charges). For each additional charge you expend you may cast the spell at a higher level. If
you expend the final charge, roll a d20, on a 1
the staff explodes in a 10 ft radius centered on you, dealing 5d10 Necrotic damage (no save), and every other creature in the area must make a Con saving throw (DC 15