BALAN WONDERWORLD

Cast members are the people that you see in all levels dressed in the various costumes you find within that chapter. They typically look like they're dancing or cheering you on. When you encounter a Negati while cast members are present, they will run around in a frenzy and disappear after a short time. Sometimes, a cast will not disappear and continue to run around for a longer period of time. This is how you get the trophy. You must catch the fleeing cast member which will then give you their associated costume instead of finding it in the level with a key. Chances are that you will run into a fair amount of catchable fleeing cast members as you go through the story, so you should not have too much trouble with this.