Staff of Mithrallus (5e Equipment)

Wondrous item (quarterstaff), artifact (requires attunement)

Combining the Crystal of Mithrallus with a Staff of Power gives you this item. For the fusion to work, a creature has to be attuned to the Staff of Power.
When combined for the limited duration, the staff emanates an ancient, prehistoric aura.

Sacrifice. When combining the Crystal of Mithrallus with the Staff of Power, the creature that is attuned to the staff of power suffers greatly to prepare its vessel for a greater purpose.
The staff of power loses all its special features. The attuned creature loses half its maximum hit points, all its Hit Dice, gets a -5 to AC and a -2 to all Ability Scores.

Godhood. The staff has a 10th level spell slot which can only be used to upcast spells (there are no new spells added).
The spellslot regenerates every 1d100 minutes and can be used at will.

Brain Expansion. You gain a +4 to either Intelligence, Wisdom or Charisma.
This bonus is set upon creation but can be chosen by the combiner and cannot give you an Ability Score that is over 30.
Also your save DC in increased by 2.

Exotic. Your level is regarded as 4 higher than your current level for determining what creatures your can transform in with spells like Polymorph and Shapechange.

Limited. The Staff of Mitrallus can be broken with a successful Strength check of 28, releasing its remaining energy.
Breaking it this way causes all creatures within 60ft to take 10d10 force damage on a failed DC 25 Constitution saving throw or half on a successful one.
The staff withers away naturally after 24 hours of coming into existence.