Unearth skull

By touching the earth, the Wizard is able to drag from earth any one skull (or big bone) even several feet under.

The corpse imbued with gentle repose are not reachable by this spell.

The wizard can use a bonus action to paint the skull with oil and gold, in order to have a gilded skull (for other spells, like Summon Undead - Nec 3rd, XgtE)