In nature, there is nothing more dangerous than a crack. And cracks can be found in every material. The world is a minefield of cracks, also known as a crackfield.

Rock can crack - this is known as a boulder. Ice can crack - this is known as an ice cube. Metal can crack - this is known as broken metal. And don't even get me started on plastic! Plastic is nothing but cracks.

However, the most dangerous crack is a crack in a truck full of liquid nitrogen. Here's what happens when a crack appears in a truck full of liquid nitrogen:
1) The liquid nitrogen comes out.
2) Due to being very cold, the liquid nitrogen freezes a cop.
3) The cop explodes into a million metallic pieces.
4) A few minutes later, the warmth of a nearby pit of molten metal causes the cop to melt back together.

Thank goodness for molten metal. Molten metal is, I suppose, the natural predator of cracks.