ThemeX is awesome, as the other commenter said, but the process can be even easier! Many icon packs are set up to work with the Android image picker. If you don't have a default gallery app set, when picking a bitmap inside Zooper, you'll be prompted to choose from various apps (gallery, camera, etc.) As well as any icon packs that support this feature. Depending on the dashboard the icon pack uses, you will hopefully be able to set your bitmap image directly from the icon pack. I've had success with this method with quite a few packs, but I've never used Coconut, so I can't comment on that one specifically. Give it a try, though.
You could make an entire screen-sized GIF that only had that part animated, then use the GIF as a wallpaper on your lockscreen.