Question: Which phenomenon said to be often seen on the Mekong River is  Mekhong Full Moon Party about

Context paragraphs:
Mekong River massacre: The Mekong River massacre occurred on the morning of 5 October 2011, when two Chinese cargo ships were attacked on a stretch of the Mekong River in the Golden Triangle region on the borders of Myanmar (Burma) and Thailand.  All 13 crew members on the two ships were killed and dumped in the river.  It is the deadliest attack on Chinese nationals abroad in modern times.  In response China temporarily suspended shipping on the Mekong, and reached an agreement with Myanmar, Thailand and Laos to jointly patrol the river.  The event was also the impetus for the Naypyidaw Declaration and other anti-drug cooperation efforts in the region.

Mekong Delta: The Mekong Delta (Vietnamese: "Đồng bằng Sông Cửu Long" , "Nine Dragon river delta" or simply Vietnamese: "Đồng Bằng Sông Mê Kông" , "Mekong river delta"), also known as the Western Region (Vietnamese: Miền Tây ) or the South-western region (Vietnamese: Tây Nam Bộ ) is the region in southwestern Vietnam where the Mekong River approaches and empties into the sea through a network of distributaries.  The Mekong delta region encompasses a large portion of southwestern Vietnam of over 40500 km2 .  The size of the area covered by water depends on the season.  The region comprises 12 provinces: Long An, Đồng Tháp, Tiền Giang, An Giang, Bến Tre, Vĩnh Long, Trà Vinh, Hậu Giang, Kiên Giang, Sóc Trăng, Bạc Liêu, and Cà Mau, along with the province-level municipality of Cần Thơ.

Ethnic groups in Cambodia: The largest of the ethnic groups in Cambodia are the Khmer, who comprise approximately 90% of the total population and primarily inhabit the lowland Mekong subregion and the central plains.  The Khmer historically have lived near the lower Mekong River in a contiguous arc that runs from the southern Khorat Plateau where modern-day Thailand, Laos and Cambodia meet in the northeast, stretching southwest through the lands surrounding Tonle Sap lake to the Cardamom Mountains, then continues back southeast to the mouth of the Mekong River in southeastern Vietnam.

Jira Maligool: Jira Maligool (Thai: จิระ มะลิกุล ; rtgs: Chira Malikun ; born 1961) is a Thai film director, screenwriter and producer.  He has directed three films, "Mekhong Full Moon Party", "The Tin Mine" and "Seven Something" (part 42.195), and was the screenwriter behind the international hit, "The Iron Ladies".

Loei River: The Loei River (Thai: แม่น้ำเลย , rtgs: "Maenam Loei" ,  ] ) is the one of tributaries of the Mekong River.  It originates at the western shore of the Phu Luang plateau, at first flowing southwards.  Changing to an eastward direction it becomes the boundary between Loei and Phetchabun Province, encircles the Phu Ho mountain and then flows northwards across the town Loei until it and mouths to the Mekong River in Na Sao Subdistrict, Chiang Khan District.

Tonlé Sap: Tonlé Sap (Khmer: ទន្លេសាប ] , literally large river (tonle); fresh, not salty (sap), commonly translated to "Great Lake") refers to a seasonally inundated freshwater lake, the Tonlé Sap Lake and an attached river, the 120 km long Tonlé Sap River, that connects the lake to the Mekong River.  They form the central part of a complex hydrological system, situated in the 12876 km2 Cambodian floodplain covered with a mosaic of natural and agricultural habitats that the Mekong replenishes with water and sediments annually.  The central plain formation is the result of millions of years of Mekong alluvial deposition and discharge.  From a geological perspective, the Tonlé Sap Lake and Tonlé Sap River are a current freeze-frame representation of the slowly, but ever shifting Lower Mekong Basin.  Annual fluctuation of the Mekong's water volume, supplemented by the Asian Monsoon regime causes the unique flow reversal of the Tonle Sap River.

Naga fireball: Naga fireballs (Thai: บั้งไฟพญานาค ; rtgs: bang fai phaya nak ), also known as bung fai paya nak or Mekong lights, are a phenomenon said to be often seen on the Mekong River.  Glowing balls are alleged to naturally rise from the water high into the air.  The balls are said to be reddish and to range in size from smaller sparkles up to the size of basketballs.  They quickly rise up to a couple of hundred metres before disappearing.  The number of fireballs reported varies between tens and thousands per night.  The phenomenon is named after the Phaya Naga, legendary serpentine creatures said to live in the Mekong.

Mekhong Full Moon Party: Mekhong Full Moon Party (Thai: 15 ค่ำ เดือน 11 ; rtgs: Sip Ha Kham Duean Sip Et ; literally, "The 15th Day of the 11th Month") is a 2002 Thai comedy-drama about the Naga fireballs that arise from the Mekong at Nong Khai on the full moon in October.  Written by Jira Maligool, the film was also Jira's directorial debut.

Songkhram River: The Songkhram River (Thai: แม่น้ำสงคราม , rtgs: "Maenam Songkhram" ,  ] ) is the one of tributaries of the Mekong River.  It originates in the hills between Nong Han district, Udon Thani Province and Sawang Daen Din district, Sakon Nakhon Province.  Outing there, it flows through Seka district (Nong Khai Province), Wanon Niwat (Sakon Nakhon Province), Si Songkhram district and mouths to the Mekong River in "tambon" Chai Buri, Tha Uthen district, Nakhon Phanom Province.  It is 420 km long.

Pak Ou Caves: Near Pak Ou (mouth of the Ou river) the Tham Ting (lower cave) and the Tham Theung (upper cave) are caves overlooking the Mekong River, 25 km to the north of Luang Prabang, Laos.  They are a group of two caves on the west side of the Mekong river, about two hours upstream from the centre of Luang Prabang, and have become well known by tourists.

Supporting paragraphs: Mekhong Full Moon Party Naga fireball
Answer: Naga fireballs