Here is your short paragraph on Pitri-Paksha:
Pitra-Paksha (Pitr-paksh) or the fortnight of the Pitris or divine fathers, also known as Mahalaya Amavas falls in the month of the September.
This name is applied to the sixteen consecutive lunar days which are devoted to the performance of Shraddhas and of deceased relatives.
Pitri Paksha is observed widely in India. The full month of Ashvina has a special force in Kashi, Prayaga, Gaya and few other tirthas, which are said to be good places for benefiting the dead. People visit Kashi at this time for shraddha rites which they perform at Manikarnika Kund in Kashi or at Pishachamochana tank on the western skirts of the city.
In Pishachamochana tank, those who perform shraddha here might add force to their rites by driving a strike into the trunk of an old tree in the temple courtyard, thus assuring that the pishacha (goblins) will be left behind or liberated. This rite is performed for those where departed loved ones have met an untimely or accidental death.
Before leaving, those who perform these rites will certainly have the darshana of Pischachamochana himself, whose round head occupies the sanctum of the temple.