Gemara

If Levi told Yehudah 'acquire like a donkey', he does not acquire;

(Rav Nachman): If he said 'you and the donkey should acquire', Yehudah receives half.

(Rav Hamnuna): Yehudah receives nothing.

(Rav Sheshes): Yehudah receives everything.

Kidushin 51a (Abaye): Kidushin that forbids Bi'ah is Kidushin;

(Rava): It is not Kidushin;

Question (Rava - Mishnah): A case occurred in which a man gave dates to five women, two of whom were sisters, and said 'all of you are Mekudashos to me.' Chachamim ruled that the sisters are not Mekudashos.

This implies that the three other women are Mekudashos. He did not say 'all of you are Mekudashos to me', for this is like saying 'you and the donkey should acquire', which does not work. Rather, he said 'one of you is Mekudeshes to me', and neither sister is even Safek Mekudeshes!

Answer: The case is, he said 'I am Mekadesh whichever of you may have Bi'ah with me.' Chachamim ruled that the sisters are not Mekudashos.

Kidushin 27a (Mishnah): Metaltelim are acquired Agav (along with) land, through money, a document, or Chazakah.

The Halachah is, the giver must say 'Agav'.

Rishonim

Rif: The Halachah follows Rav Nachman in monetary laws.

Rambam (Hilchos Mechirah 22:12): If one was Makneh (transferred ownership) to any kind of animal, it does not acquire. If one was Makneh part of his property to an animal or someone (a fetus) not yet in the world, and then told Yehudah 'acquire like this animal or like this fetus', he does not acquire. If he said 'you and the donkey' or 'you and the fetus should acquire', Yehudah receives half.

Rambam (Hilchos Ishus 9:2): If one was Mekadesh many women at once, and said 'all of you are Mekudashos to me', and among them were two sisters, none of them are Mekudashos. If he said 'I am Mekadesh whichever of you may have Bi'ah with me', they are all Mekudashos, except for the two sisters.

Rosh (Kidushin 2:22): The Rif did not bring this, for he holds that Rava's question (this is like 'you and the donkey...') is unlike the Halachah. We hold like Rav Nachman in monetary laws, and he holds that if one said 'you and the donkey...', the recipient acquires half. Abaye establishes the Mishnah to be when he said 'all of you.' The Gemara often tries to establish the Mishnah like all Amora'im, even if the Halachah does not follow them. However, Bahag establishes the Mishnah when he said 'whoever among you that may have Bi'ah with me is Mekudeshes to me.' The Ri says that Rava, who asked 'this is like 'you and the donkey...'', does not argue with his Rebbi, Rav Nachman. Rather, he asks according to the opinion that Yehudah does not acquire at all. That opinion surely establishes the Mishnah to be when he said 'one of you is Mekudeshes to me', and we do not find that Amora'im argued about how to establish the Mishnah! Some say that Rav Nachman says that Yehudah acquires half only when the Makneh's statement had two parts, 'you and the donkey...'. Here, when he said one thing, 'all of you', he agrees that nothing is acquired.

Mordechai (605): A case occurred in which one was Makneh, through Chalipin, land, Metaltelim and money at once. Some Chachamim said that this is like 'you and the donkey....' Just like money is not acquired through Chalipin, also the land and Metaltelim are not acquired. Some say that he acquires everything. Migo (since) he acquires the land and Metaltelim, he acquires also the money. R. Simchah says that even though the money is not acquired, the land and Metaltelim are acquired. He learns from Kidushin 27a. One acquires Metaltelim Agav land only if the giver said 'Agav'. If not, we do not say 'Migo he acquires the land, he acquires the Metaltelim.' Do not say that this is like 'you and the donkey...' (Hagahah - and even the land is not acquired). A donkey cannot acquire. Money can be acquired through Meshichah, Hagbahah, or Chatzer.

Poskim

Rema (203:10): If one was Makneh, through Chalipin, money and Metaltelim or money and land, some say that since money is not acquired through Chalipin, the entire Kinyan is Batel. Some say that the entire Kinyan is valid. Some say that he acquires the land or Metaltelim, but not the money. The same applies if one acquired something that can be acquired with something that cannot be acquired.

SMA (19): R. Simchah holds that he acquires only the land. He gave good reasons to reject the previous opinions, and the Mordechai cited him last. This is why the Rema (209:4) brought only R. Simchah's opinion. Here the Rema brought all three opinions, for R. Simchah discussed this law. He brought R. Simchah last to hint that he holds like him. Also, in Siman 209 the Rema brought only R. Simchah, for the opinion that says that he acquired nothing holds that 'you and the donkey...' acquires nothing, but we hold that it acquires half. This is why the Rema compares it to 'you and the donkey...'. The opinion that he acquires even the money says so because the money is in the world, and it can be acquired through Meshichah and Hagbahah, therefore Chalipin helps for it through Migo. It does not help for Davar she'Lo Ba l'Olam, which cannot be acquired at all. Terumas ha'Deshen 173 was unsure whether we say Migo. Why do the Mordechai and Terumas ha'Deshen suggest that this is like 'you and the donkey...' (and nothing is acquired), when we hold that 'you and the donkey...' acquires half? This is because the Stam Gemara in Kidushin asked according to this opinion. Since Amora'im argue about this, we leave the money with the Muchzak, and the recipient does not acquire at all.

Gra (203:42): Why did the Rema bring the first opinion? We hold that 'you and the donkey...' acquires half! This opinion is Batel, for we follow Rav Nachman in monetary laws. R. Simchah's proof is strong. Even so, the Mordechai pondered the law according to Rav Hamnuna. He rules like Rav Hamnuna against Rav Nachman, for the Sugya in Kidushin is like him. We hold like Rav Nachman. It seems that the Mordechai and Rema hold like Bahag and the Rambam (Hilchos Ishus 9:2), that the Sugya in Kidushin is even like Rav Nachman. Rav Nachman agrees that nothing is acquired when the Makneh said one inclusive statement. This answers R. Simchah's question, for there he included everything in one statement. When he makes separate statements, both opinions agree that this is like 'you and the donkey...' This is why the Rema brought two opinions here, but not in Siman 209.

Rema (209:4): If one was Makneh Davar she'Lo Ba l'Olam with Davar she'Ba l'Olam, some say that this is like 'you and the donkey...', which will be explained in Siman 210.

Shulchan Aruch (210:3): If Levi told Yehudah 'buy my property, or this item, you and this donkey' or 'you and this fetus', Yehudah receives half.

SMA (8): If one told his son David 'acquire, you and the fetus that my wife will become pregnant with', David receives half initially, and later he divides the remaining half with the fetus, when it is born.

Shulchan Aruch (EH 41:3): If one was Mekadesh many women at once, and among them were two sisters, if he said 'I am Mekadesh whichever of you may have Bi'ah with me', they are all Mekudashos, except for the two sisters. The same applies if he said 'all of you are Mekudashos to me'. Some say that none are Mekudashos, therefore, the oter women are Safek Mekudashos.

Beis Yosef (DH v'Chosav, citing the Ran): The Rif brought the Mishnah simply, for we needed to say that he was Mekadesh 'whichever of you may have Bi'ah with me' only due to the question from 'you and the donkey...', which was according to the opinion that it does not acquire at all. We hold that it acquires half, so we establish the Mishnah simply. Bahag and the Rambam explain the Mishnah the way we answered for Abaye, but if he was Mekadesh all of them, none are Mekudashos. They hold that the question was according to Halachah. A Makneh wants whoever can acquire to acquire. The Mekadesh gave the basket (only) with intent to acquire all of the women. A buyer often takes good and bad together. They hold like this so that the Sugya will be like the Halachah. We should not be lenient, for often the Gemara asks unlike the Halachah.

Gra (4,5): Most hold like the first opinion in the Shulchan Aruch. The Rosh in Kidushin holds like the latter opinion.