In Parshat Korach, Korach, Datan and Aviram (and their families and all of their posessions) are swallowed by "the mouth of the earth". The Malbim notices a couple interesting issues with this miracle, which hint at the actual uniqueness of this miracle. When Moshe explains to Am Yisrael that the miracle that is about to happen is a sign of the truth of Moshe's leadership and of Torah, he does so by saying "But if Hashem will create a new creation (בריאה), and the earth opens its mouth and swallows them and all that is theirs, and they will descend alive to the pit -- then you shall know that these men have provoked Hashem" (Bemidbar 16:30). There most obvious peshat (reading literally) would suggest that an earthquake opened up a chasm beneath Korach and his followers and they fell in. But there are a couple of reasons why this cannot actually be the case.
The word בריאה indicates creation from nothing (יש מאין), as indicated by its original context בראשית ברא אלקים את־השמים ואת־הארץ (At first, God created Heaven and Earth, Bereshit 1:1). After God created heaven and earth from nothingness, every other act of creation was to create something from something else. As a side point, the mouth of the earth definitely wasn't created at anew at the time of Korach, because Avot 5:6 says it was created bein hashmashot on the 6th day of creation. But clearly if it's a completely new creation, it cannot be an earthquake -- somehting had to be added to existance, not just reconfigured a little.
Secondly, the purpose of the miracle was to reinforce that Hashem had really chosen Moshe, and that Moshe's transmission of Torah was true (he wasn't just making things up). We see that when Moshe Rabbenu announce the death of the firstborn to the Egyptians, he told them that it would happen כחצות הלילה (at around midnight, Shemot 11:4). According to Rashi, the plauge happened at exactly midnight, but Moshe was vague about the time, so that the Egyptians inaccuracte timepieces wouldn't lead them to believe the plague wasn't at exactly midnight and therefore the plague wasn't from Hashem. The lengths people will go to to disbelieve Hashem. So clearly the plauge couldn't even resemble something natural.
Lastly, we have the location of the people who were eaten. Korach was standing at the enterance to the ohel moed, with the 250 people offering incense. His tent was in the camp of the Leviim. Datan and Aviram were in the tribe of Reuven, so their tents were located there. They were standing at the enterances to their tents with their entire families. (The Malbim says that each of these 3 locations were 2000 amot apart.) But ותפתה הארץ את־פיה (the earth opened up its mouth (singluar), Bemidbar 16:32) and swallowed Korach, Datan, Aviram their families, and posessions, and nothing else (nothing in between). With an earthquake, there could not have been a single opening that hit all 3 locations and left everything in between untouched.
The Malbim describes the miracle that occured as follows: the Earth opened its mouth underneath Korach's tent and devoured it. The mouth looked like the mouth of an animal. It moves, and it opens and closes. After devouring Korach's tent, the mouth closed and stretched out 2000 amot to Korach himself, opened one end, and devoured him. Then it closed again, and streched out 2000 amot (I supposed in the opposite direction) to the tents of Datan and Aviram, opened one end, and devoured them. And any posession of Korach, Datan, and Aviram that someone else was borrowing was magnetically attracted to the mouth.
As an aside, Rabbi Itzinger mentioned to me another reason for כחצות הלילה (at around midnight, Shemot 11:4). Each Egyptian who died in the plague died at exactly midnight, but midnight hits different locations in Egypt at slightly different times. So not all of the firstborns died at once, rather they died in a wave across Egypt, following the progression of midnight across Egypt.
The secret word of the week is הבלה דאגמא (Bava Metzia 36b).