The Yerushalmi Talmud at Shabbos 1:4 has a mysterious passage speaking of a time when Beis Shammai literally violently out-dueled Beis Hillel:
Mishna: These are the laws they said in the attic of Hanania ben Hizkiya ben Gurion, when they went in to visit him. They voted and Beit Shammai was the majority over Beit Hillel, and they decreed eighteen things in that day.
Gemara: That day was as hard for Israel as the day the golden calf was made... Rabbi Joshua Onaya taught: The students of Beit Shammai stood at the bottom [of the stairs], and they killed the students of Beit Hillel. It was taught: Six of them went up [to the attic], and the rest of them attacked them with spears and swords. It was taught: For eighteen things they decreed, and in eighteen they were the majority.
According to the Korban HaEda, this passage neither means that Beis Shammai outnumbered Beis Hillel or that, G-d forbid, Beis Shammai members actually committed murder. But during a number of votes, they did block access to Beis Hillel mebers to the beis midrash as votes were taken. Over centuries there has remained much dispute as to the meaning of this assage, for example the Karraites took up the passage with Rav Sadia Gaon who denied it ever happened. How have later commentators treated this passage?