|The "Last Supper of Osiris", before he his betrayed by his brother Set, and tricked into getting into a chest of wood, which is thrown into the Nile, after which his body is torn into 14 pieces, prior to being resurrected (see: death and resurrection of Osiris), which became, in the Roman recension (100AD-600AD), the "Last Supper of Christ", after which he is betrayed by Judas, for 30 pieces of silver, and Jesus is then whipped into pieces and "crucified" on the cross, prior to being resurrected (see: death and resurrection of Jesus).|
Osiris’ last supper
In Egyptian mythology, Osiris, as related by Plutarch, in his, famously had a “last supper” before being betrayed by his brother Set, chopped into pieces, and later put back together, in the form of a mummy, and resurrected by his wife-sister Isis.
In 100AD, Plutarch, On Isis and Osiris (100AD), summarized Osiris’ last dinner as follows: 
“During his absence the tradition is that Typhon [Set] attempted nothing revolutionary because Isis, who was in control, was vigilant and alert; but when Osiris returned home Typhon contrived a treacherous plot against him and formed a group of conspirators seventy-two in number. He had also the co-operation of a queen from Ethiopia who was there at the time and whose name they report as Aso. Typhon, having secretly measured Osiris's body can having made ready a beautiful chest of corresponding size artistically ornamented, caused it to be brought into the room where the festivity was in progress. The company was much pleased at the sight of it and admired it greatly, whereupon Typhon jestingly promised to present it to the man who should find the chest to be exactly his length when he lay down in it. They all tried it in turn, but no one fitted it; then Osiris got into it andlay down, and those who were in the plot ran to it and slammed down the lid, which they fastened by nails from the outside and also by using molten lead. Then they carried the chest to the river and sent it on its way to the sea through the Tanitic Mouth. Wherefore the Egyptians even to this day name this mouth the hateful and execrable. Such is the tradition. They say also that the date on which this deed was done was the seventeenth day of Athyr, when the sun passes through Scorpion, and in the twenty-eighth year of the reign of Osiris; but some say that these are the years of his life and not of his reign.”
In 1907, Gerald Massey, citing Plutarch, summarizes this as follows: 
“As the legend is related by Plutarch, the death of Osiris was preceded by his betrayal, and the betrayal, which was the work of his twin brother, Sut, took place in the banqueting-room. Sut, having framed a curious ark just the size of Osiris's body, brought it to a certain banquet. As this was on the last night of Osiris's life or reign, and on the last night of the year, the meal may fairly be called the Last Supper.”
Jesus’ last supper
In Christianity, Jesus, who is the Roman recension rescript of Osiris and or Osiris-Horus, had a purported “Last Supper”, as described in Matthew 26:17–29; Mark 14:12–25; Luke 22:7–38; I Corinthians 11:23–25, characterized as the final meal shared by Jesus and his disciples in an upper room in Jerusalem, the occasion of the institution of the Eucharist (Ѻ).
In 2008, Dorothy Murdock, building on Massey, in her Christ in Egypt: the Horus-Jesus Connection, summarized the main points of "Osiris + Horus = Jesus" syncretism as follows: 
“In ancient mythology, in which immortal gods can die, the death of a deity is very significant and is often attended by a sentiment of redemption and salvation, such as the ultimate sacrifice of god's son in Jesus Christ. We have already seen how Osiris and Horus both were betrayed and murdered by their brother/uncle Typhon/Set, with Osiris's death plotted during a sort of "Last Supper" gathering. But were either Osiris or Horus "crucified," as has been claimed by a number of writers? Firstly, when it is asserted that Horus (or Osiris) was "crucified," it should be kept in mind that it was not part of the Osiris/Horus myth that the murdered god was held down and nailed to a cross, as we perceive the meaning of "crucified" to be, based on the drama we believe allegedly took place during Christ's purported passion. Rather, in one myth Osiris is torn to pieces before being raised from the dead, while Horus is stung by a scorpion prior to his resurrection.”
Here, Murdock's mention of Osiris' death plotted during a sort of "Last Supper" refers to how the story of Set inviting Osiris to a big dinner and then tricking him into getting into a "chest" that just fit the body size of Osiris, after which he threw the chest into a river (see: Christmas tree), became the New Testament story of the final meal, aka Last Supper (Ѻ), that, in the Gospel accounts, Jesus shared with his Apostles in Jerusalem before his crucifixion; during the meal Jesus predicts his betrayal by one of the apostles present. In the original version, Set betrays his brother Osiris during Osiris’ last meal.
1. Plutarch. (c.100AD). Isis and Osiris; in: Plutarch's Moralia, Volume Five: Isis and Osiris. The E at Delphi. The oracles at Delphi no longer given in verse (§:1-19; §:20-40; §:41-50: §53-67; §:68-80) (Last Supper, pg. 13). The obsolescence of oracles (Introduction: Victor Hanson). Harvard University Press.
2. Massey, Gerald. (1907). Ancient Egypt: The Light of the World: a Work of Reclamation and Restitution in Twelve Books, Volume Two (§: The Last Supper: the Crucifixion and the Resurrection, pg. 868-). T. Fisher Unwin.
3. Murdock, Dorothy M. (2008). Christ in Egypt: the Horus-Jesus Connection (pg. 335). Stellar House Publishing.
● Thims, Libb. (2018). “Osiris Jesus Last Supper” (Ѻ), Atheism Reviews, Jan 8.
● Last Supper – Wikipedia.