This achievement requires you to kragelize 10 enemies with the Kragle Gun that Lord Business (Minifigure) has by simply shooting them, any enemy counts and if you wish you can even kragelize your second character though that is slower.
You can aim and shoot people by holding
but the easiest way is to hold
Lord Business (Minifigure) is unlocked after you complete the story and costs 1,000,000 studs.
Here's a video.