In Numbers 16, Korah and his companions challenged Moses's leadership. How did God respond?

By burying them alive along with their families

Now Korah, the son of Izhar, the son of Kohath, the son of Levi, and Dathan and Abiram, the sons of Eliab, and On, the son of Peleth, sons of Reuben, took men:

And they rose up before Moses, with certain of the children of Israel, two hundred and fifty princes of the assembly, famous in the congregation, men of renown:

And they gathered themselves together against Moses and against Aaron, and said unto them, Ye take too much upon you, seeing all the congregation are holy, every one of them, and the LORD is among them: wherefore then lift ye up yourselves above the congregation of the LORD?

...

And the LORD spake unto Moses and unto Aaron, saying,

Separate yourselves from among this congregation, that I may consume them in a moment.

And they fell upon their faces, and said, O God, the God of the spirits of all flesh, shall one man sin, and wilt thou be wroth with all the congregation?

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If the LORD make a new thing, and the earth open her mouth, and swallow them up, with all that appertain unto them, and they go down quick into the pit; then ye shall understand that these men have provoked the LORD.

And it came to pass, as he had made an end of speaking all these words, that the ground clave asunder that was under them:

And the earth opened her mouth, and swallowed them up, and their houses, and all the men that appertained unto Korah, and all their goods.

They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation. Numbers 16:1-33