What do you think will happen if Conversion Bureau targeted the EqG world?

[HorsesandMOARGaloar 300]

The Conversion Bureau is a series of fanfics where Equestria suddenly appears on an ocean (usually the Atlantic), and a magic barrier is set up that expands to the whole world, killing anyone it touches. The Equestrians, under Princess Celestia, attempt to force all Humans to take up a serum that transforms Humans into more Equestrians, sparking various wars.

 

It would be very interesting if TCB reached "Canterlot-ia", where Sunny has "all this awful conflict with humanized Twily", but now has to face magical ponies who act like conquering tyrants, and a lethal barrier that grows every day.

 

What would happen?