WHAT COULD IT BE?

umm no, dont use a crowbat and just put all of youre strength in it, youll mess up the gasket sealing surface since it is aluminum. and DO NOT use a freaking metal hammer, i hope the guy that was suggesting that was messing around. Just take a flatblade screwdriver with a clean rag over it and open it up, you cant just put pressure on one side, you have to get another screwdriver and do it to the other side at the same time. It has to lift striaght up, not one side up and then the other
 
umm no, dont use a crowbat and just put all of youre strength in it, youll mess up the gasket sealing surface since it is aluminum. and DO NOT use a freaking metal hammer, i hope the guy that was suggesting that was messing around. Just take a flatblade screwdriver with a clean rag over it and open it up, you cant just put pressure on one side, you have to get another screwdriver and do it to the other side at the same time. It has to lift striaght up, not one side up and then the other

or he could just buy the CORRECT tool which is a case splitter.
if your prying on the motor and kicking it and so on you might as well throw it away because you may have damaged it.
why cant people just use the right tool for the right job come on guys...