What are the physics behind launching a turd into LEO so large, that it descends back to Earth at a desired target, blowing up the target, while leaving a stinky crater?

The turd must be large enough to survive re-entry into the atmosphere while damaging a desired target with the equivalent of a turd meteor or comet. I want my adversary to be not just covered in poo, but I want them to be blown up BY poo, while leaving a stinky crater for generations to inhale as they gaze upon my poohole

When I go to launch, how large must the turd be to survive reentry into the atmosphere? I'm thinking about 4 tons.

Thoughts?