Here's how Fantastic Beasts star Ezra Miller was transformed into an Obscurus using special effects
Take a look at behind-the-scenes footage to see the VFX wizardry in Fantastic Beasts and Where To Find Them
How do you turn Ezra Miller's Credence Barebone into a malevolent Obscurus, or have Newt Scamander (Eddie Redmayne) stroke the beak of a Thunderbird called Frank? The answer, of course: with a truckload of special effects.
Double Negative, the VFX company who brought the world of Fantastic Beasts and Where To Find Them to the big screen, has released a video showing what the footage looked like before they added CGI and afterwards. The transformation is so impressive it's just like real magic.
This behind-the-scenes video reveals the little tricks behind creating that magic: antique cars being thrown around by cables and pulleys, a props guy holding a giant bird-head while Redmayne strokes it, and acres of green screen.
So back to the question of how to turn Credence Barebone into a malevolent Obscurus...
http://www.giphy.com/gifs/xThtac1U1Mqyp0nAjK
It turns out all you need to do is have Ezra Miller stand in front of a green screen and vibrate, furiously.