Curve ball = swirl your finger on the ball to make it spin. Then throw it to the side of your screen and it will ‘curve’ over and smack the critter on top of its head. Or you’ll totally miss. They take practice and dumb luck. BUT the catch rate is better, so if you make it you might not have to use more balls.
I name my pokemon by randomly swiping letters and picking the first name it gives me. Except for Kevin. Kevin is a purple stink ball because um, reasons.