Discord explain the destructive results of a full on confrontation.
 
I guess you could call it - the chaos theory. Chaos’s destructive theory. For that’s all it could be – a theory. For if it has ever happened before, it wouldn’t have. For such an event would in itself result in its own erasing.
 
For such a confrontation would result in so much chaos, that the combatants, and everything around them would overflow, and result in a quantum collapse. everything would be filled with so much chaos that it would cease to be on this plane of existence.
 
To show that he was serious, Discord showed fluttershy a fraction of his true form (not that he has a “real” from) But the form he has taken to exist on the physical plane. That form would be destroyed. along with everything around him. All his memories, and the memories other have of him, everything that his existence has caused and affected would be dragged down into the infinite hole of oblivion, as it would be filled with so much chaotic energy - that it ceased to be a tangelible thing.
 
there would not be any octopus with bunny ears. or talking balloon animals. there wouldn’t even be tentacles or non euclidean geometry, reality wouldn’t even become like mist upon the rivers of time. it would all become pure energy, not even an ethernal darkness would await, but simply the blinding  
light of non existence from the original chaos that spawned the universe. like the collision of matter and anti matter, all would be sucked down that hole to never exist, ever have existed, or ever going to exist.
 
Though… Fluttershy looks like she would no mind some chaos right now.  
(you know - in moderate amounts.)