After talking to a trainer ( the guy in front of the tree), I encountered a pokemon. For some reason, (even though my pidgey was leading the party) my oddish came out. It had the same moveset as my pidgey. When I used the third move (gust), it came out as absorb (my oddish's move). I was suprised and wanted to test what would happen if I used the fourth move (my oddish only has 3). This caused the game to freeze, and kick me out of the game. I did nothing but encounter the pokemon. I didn't switch anything.