Pepper’s Ghost Hologram Flask – Make:

Before settling on a final subject matter for your Mad Scientist Pepper’s Ghost Chemistry Flask, it’s a good idea to test out what you’ve made so far to ensure that the effect is working. Find a video or image on a black background. Anything black in a Pepper’s Ghost illusion becomes transparent, so the focus of the video will appear to float.

A quick Google search will yield loads of stock video of various creatures and objects against a black background. Find one with bright colors against that very dark or black background, There’s one in particular that I use so often that I paid for an HD version of it, and the goldfish has sort of become my mascot.