What is this effect called?

Rerun

L1: Registered
Dec 26, 2015
23
5
I have seen this thing in a lot of subgame maps, although I don't know what the entity is called in hammer, and I need to know. It was used in a lot of deathrun maps, such as bank (where the screenshot is from) and I was planning to use this thing in maps. If anyone knows the name of this effect, tell me. Thanks. image.jpg