The CW has released this video showing the visual effects for the Parasite episode of Supergirl from earlier this season. The episode was called Changing, the sixth of the season, and featured scientist Rudy Jones becoming the classic DC villain. It also showed us both Mon-El and Guardian in action after Supergirl and J'onn J'onzz were drained by Parasite. There's no dialogue in the video, but you can see from the different effects shots how many different layers are needed for some of what look like simple scenes and how much of the shots are practical compared to computer generated.
Supergirl will return on April 24th.