As Ditto saw the Skarmory pull back, and come in with another Steel Wing, he took a defensive stance and braced for the attack. When it hit, he used Counter, which takes all the damage done and throws it back twice over. Since this time the Steel Wing wasn't met with an equal attack, it hurt a bit, but that was how Counter worked. If you don't take much damage, you can't dish much out, even at double strength. His trainer, Cody, had considered teaching Chansey the move, since she had high health, and low defense, but so far he hadn't.