From the National Catholic Register:
Throughout the centuries, humanity has relished in ghostly accounts such as these. Some listeners instinctively dismiss these tales with logic. As Catholics, we should never actively seek out contact with the dead (see Catechism 2116). But some of us may inadvertently experience what can only be described as paranormal.
One such visit occurred when Padre Pio was praying in the chapel. Looking up at the sanctuary, he noticed a friar bustling about, dusting around the high altar. The ghost identified himself as a friar who had served his novitiate at the monastery and was given the task of setting up the altar for Mass. However, due to instances of irreverence he committed in life, the ghostly friar was still in Purgatory, seemingly doing penance by performing his earthly duty with greater diligence. The poor soul begged Padre Pio to pray one Mass for him so he might be freed from the suffering of Purgatory and finally enter Heaven.