Material Effect on UI

Hey guys,
I have a simple question: I have a UI material which I lay over the UI in UMG, but I reach the limits of my knowledge here. Is it possible somehow to get the underlying UI as a texture to work with it in a material, similar as PostProcessInput0 or SceneTexture works in Surface materials? To be specific: I want a glitch effect on the main menu (like this), but I think I cannot do it like this way, but I don’t want to prerender everything as movies and then just play them in the main menu…
Any ideas on this? Thank you!