The way I did this video was I took the cube and froze it in the freezer and then I placed it in something that will hold the water and used a blow dryer and melted the ice. It took about 20 minutes to do that. Then I froze the cube again in the same way and the smashed it.
The problem that I ran into while melting it was the air being blown moved the cube around a bit and I thought it would ruin the video but I kind of masked that by using stormy weather sounds and when the cube moved I made lightning and thunder sounds, thus adding to the effect and I think it turned out really good.
Yes, the cube broke too. It's in the garbage in pieces.