This achievement is story related and cannot be missed.
This achievement can be earned in the second world "Deserts of Dijiridoos" on the first level ""Crazy Bouncing." On the 3rd stage of the level you will see Holly trapped by a Darktoon who will begin fleeing. The chase will be brief and the enemy will start to slow down, giving you the chance to free the Nymph. When this happens either punch, kick, or head bop the enemy to free her. You will be awarded a special ability and 15G!