Illusion

I accidentally found that my magic wand had fooled me. It reserved half of its power.

I was by then taking pictures of a caterpillar. Trial makes perfect; back and front light, and whatsoever techniques I have read, I put into practice. 

My magic wand started functioning when a band of rainbow appeared on the camera screen.

It changed the transparency of the caterpillar, like how I alter the transparency of a solid fill in Microsoft Office.

That was interesting, I waited more. I could be Merlin or David Copperfield in the next second. 

But it stopped, absurdly.

The caterpillar stayed half-disappeared. My left half was Rainfield, another half  David Copperfield.