Causes of engine block crack?

Just wanted to get some foresight on potential causes of a cracked block. Tore apart my motor today expecting a cracked head gasket since I was getting coolant in cylinder 3. Couldn’t find anything until I looked at the piston head and realized it’s completely destroyed, and that the blunder wall cracked into the cooling jacket. What could be the cause of this? Thanks FABOIMG_0160.jpegIMG_4247.jpegIMG_4251.jpegIMG_4253.jpeg