Good & Bad Ghosts

From BoardGameGeek:

In Good & Bad Ghosts!, each player has four good ghosts and four evil ghosts – but only the player who owns a ghost can see whether it's good or evil (as with the pieces in Stratego). These ghosts start the game in the back rows of a 6x6 game board with the corners removed. Each turn, a player moves one of his ghosts one square orthogonally. Moving into an opponent's ghost kills that ghost. To win, you must get rid of your own evil ghosts, kill your opponent's good ghosts, or move one of your good ghosts off the board from one of your opponent's corner squares.