A megacryometeor is a very large chunk of ice, weighing at least 10 kilograms, that are sometimes called huge hailstones, but don't need to form in thunderstorms.
Size
More than 50 megacryometeors have been recorded since the year 2000. They vary in size between 10 kg to over 200 kg. One was measured in Brazil as 220 kg.
What are they?
They are sometimes confused as meteors, because they can leave impact craters. The difference between a megacryometeor and a hailstone is not clearly defined, mostly because the process that creates megacryometeors is not fully understood, but they have been recorded falling out of a clear sky on a hot summer day. They are also not made from air-plane toilets or exhaust streams. All analysis of the ice shows it matches normal rain for the region it fell on.