1)
Who was burned?
1.
Rashi: "Va'Tochal Es ha'Chamishim u'Masayim Ish Makrivei ha'Ketores" (Bamidbar 16:35).
2)
Why does it say "Lehavah Telahet"?
1.
Radak: The matter is repeated in different words.
2.
Malbim: After mentioning swallowing and burning, this hints to the third punishment. It is as if a flame separated and burned from afar, i.e. a plague.
