Seastone negates devil fruit powers, we know that much. Now, what if someone was in the midst of using a devil fruit power, which would destroy a normal person. What would happen to them? Would they fall apart? Would they stay like that forever? Would they be in great pain? Would they revert to normal size, but be able to use DF after that?
Take Luffy
In Mid stretch. That would rip the skin, and bones apart.
Take Buggy
Sliced apart, he would die from blood loss and flal on the ground in pieces.
Take Mr. 5.
In Mid explosion, he would be disenegrated or burned horribly forever.
Take Ms. Valentine
If she was light, she would float away forever
If she was heavy, she would have a hard time walking. Let alone crawling.
Theres a lot of possibilities. Discuss what u think might happen.