One of Luka’s skills, the Fallen Angel Dance is a skill which Luka activates under the influence of holy power while he is asleep.
It is very similar to Serene Mind, and it avoids every attack.
There is a high possibility that Luka will learn to use this in Chapter 3.
The effect used is a shorter version of the "sleep waves" as Luka is falling asleep in the beginning of the game just before he speaks with Ilias.