parshanut torah comment - What is the plague being referred to in Parshas Korach?

Bamidbar 17:11

ויאמר משה אל אהרן קח את המחתה ותן עליה אש מעל המזבח ושים קטרת והולך מהרה אל העדה וכפר עליהם כי יצא הקצף מלפני יהוה החל הנגף

And Moses said unto Aaron: 'Take thy fire-pan, and put fire therein from off the altar, and lay incense thereon, and carry it quickly unto the congregation, and make atonement for them; for there is wrath gone out from the LORD: the plague is begun. (Translation from Mechon Mamre, emphasis added)

The word הנגף has a ה הידיעה, definitive article identifying it as a known entity. Is there some specific plague being referred to here?

Answer

Targum Pseudo-Yonasan on "כי יצא הקצף מלפני ה׳" renders:

ארום נפק מחבלא דאתכלו בחורב דשמיה קצף מן קדם ה׳ בהורמנא

That is (apparently):

for a destroyer which was withheld at Horeb, whose name is קצף, has come out from before God with a command(? permission?)

The anonymous "Perush Yonasan" in my Chumash explains:

When Moses was on Horeb to receive the tablet, Israel sinned. Five destruction angels were joined to it. When it was suspended in the merit of the three patriarchs, three left and two remained. Thus it is in a midrash. Now, though, they came out with permission from God, as it says "כי יצא הקצף מלפני ה׳". See Recanati, which cites the view of our master [pseudo-Yonasan] that they're unable to do their work except with His (blessed is he) authority, which is why he translates as "בהורמנא".

(Rabbi Recanati (according to this version (1.4 megabytes)) says on this verse:

פירוש בסוד קץ כל בשר בא לפני כי צריך ליטול רשות קודם שיעשה פעולתו וכן רמז יונתן בן עוזיאל ע״ה ארום נפק מחבלא ואתכלי בחורב דשמיה קצף מן קדם ה׳ בהרמנא שרי לקפלא. וטעם ויעמוד בין המתים ובין החיים כטעם אשר הערה למות נפשו (ישעיה ג׳ יב׳) והבן זה

… which I won't attempt to translate.)

So it seems the plague is one previously known to Moshe (and perhaps which he previously told Aharon about).