It is satan, he will be naked and shamefully exposed because it is the righteousness of Christ that will be covering the other wedding guests. He will also be speechless because by then he will have no defence in front of God at all. This verse where satan is described as a man is in reference to:
Isaiah 14:16
Those who see you stare at you, they ponder your fate: "Is this the man who shook the earth and made kingdoms tremble,
This parable is all about Gods plan for mankind:
The Parable of the Wedding Banquet Explained
Matthew 22
2“The kingdom of heaven is like a king who prepared a wedding banquet for his son.
This is when God the Father made the Heavens and the Earth, and prepared a plan for Mankind and Jesus to be together forever.
3 He sent his servants to those who had been invited to the banquet to tell them to come, but they refused to come.
God sent the Old Testament Prophets to tell people that Jesus was going to come but the people rejected Jesus and killed Him.
4“Then he sent some more servants and said, ‘Tell those who have been invited that I have prepared my dinner: My oxen and fattened cattle have been butchered, and everything is ready. Come to the wedding banquet.’
These are the Christians who have been telling the World that Jesus is going to return.
5“But they paid no attention and went off—one to his field, another to his business. 6The rest seized his servants, mistreated them and killed them. 7 The king was enraged. He sent his army and destroyed those murderers and burned their city.
This is Jesus' second coming.
8“Then he said to his servants, ‘The wedding banquet is ready, but those I invited did not deserve to come. 9 So go to the street corners and invite to the banquet anyone you find.’
This will be during the Millennial reign of Christ.
10 So the servants went out into the streets and gathered all the people they could find, the bad as well as the good, and the wedding hall was filled with guests.11“But when the king came in to see the guests, he noticed a man there who was not wearing wedding clothes. 12 He asked, ‘How did you get in here without wedding clothes, friend?’ The man was speechless.
This will the great white throne Judgement and the Wedding of the Bride and Christ. satan is that man. He will have no defence left and is not covered by Jesus' righteousness.
13“Then the king told the attendants, ‘Tie him hand and foot, and throw him outside, into the darkness, where there will be weeping and gnashing of teeth.’14“For many are invited, but few are chosen.”
At the Wedding banquet will be the Great Multitude who were invited and the 144,000 who are the chosen.