User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5020152-20141013193126

Here's a little theory based on something that MHAdvent said recently.

I think that the Gore Magala variant (the one halfway between Gore and Shagaru) is an individual that was born with a one-in-a-million genetic mutation that halted its transition between the two stages, leaving it in that strange halfway state. Also, because of this mutation, its virus is a lot more potent and is capable of inflicting the Extreme state on other monsters.