On your moon, open your Popit and head to the goodies bag. Plonk down an item, then head over to tools. You can put an emitter or anything you want on there really, just tweak it as you need to and away you go. Go and get the capture item tool, hold it over your item and save it.
If doing at the same time as Arms Creator (may as well, really..) Popit - Tools - Page 3 Powerups - Specific Weaponator. Place, choose your loadout. You may need to capture the item to pop the trophy.