PlayStation Move Heroes

This trophy can be quite hard to get. I got it in Lash Gasp in Gleebertopia. After you complete Wave 1, you'll be teleported to an island where Wave 2 starts. Exactly eight pirates should come at you from behind the boxes that explode. Run around them in circles to group all of them together. Then throw Groovitron in the middle to make them all dance. Charge the whip by holding the motion controller above you and land a powerful slam in the middle of the dancing pirates. This should kill them all.

Another good spot to get this is during 40 Lash Gasps!, the Diamond Challenge in Gleebertopia. This is best done at the beginning of the 3rd Wave in this survival challenge, when you are completely surrounded by 10+ enemies. Just run around them in a circle to get them rounded up and do the whip smash technique to kill most of them. The whip smash is the one where you hold the Move back behind you to power up the meter in the lower left until it's full, then swing the Move controller directly forward in front of you.