Nazir 5:1

Beis Shammai say that if something is accidentally consecrated, it is consecrated; Beis Hillel say that it is not, as follows: If one says, “The black ox that exits my house first is consecrated” and a white ox comes out, Beis Shammai say it is consecrated and Beis Hillel say it isn’t.

Nazir 5:2

If a person says, “The gold coin that comes into my hand first is consecrated” and he pulls out a silver coin, Beis Shammai say it is consecrated and Beis Hillel say it isn’t. If a person says, “The barrel of wine that comes into my hand first is consecrated” and he grabs a barrel of oil, Beis Shammai say it is consecrated and Beis Hillel say it isn’t.