Grazing is one of the lesser known abilities you have in a lot of games in the top down shooter category. Your hitbox is often not to the size of the character model, rather, it's usually a very small circle located in the middle of the character you are controlling.
Some games, such as as the games in the Touhou series, have a button which actually shows you the hitbox of a specific character, which are known to actually vary depending on which character you are using. For instance the character "Reimu Hakurei" is famously known for having a smaller hitbox then other characters you can play as.
In a lot of topdown shooters, knowing where your hitbox is, and how big it is can be essential to doing the best you possibly can at the game, even in the games where you aren't given a button to see it.