Who led the rebellion in which the ground split open and swallowed the rebels?

Answer: Korah

Korah and his followers rose against Moses and Aaron; the earth opened its mouth and swallowed them and their households.

“Now Korah son of Izhar, the son of Kohath son of Levi, along with some Reubenites—Dathan and Abiram, sons of Eliab, and On son of Peleth—conducted”— Numbers 16:1 (BSB)