This is what you say when a child is being toxic or is getting salty in video games such as: Fortnite: Battle Royale, Overwatch and League Of Legends. If you use this insult on a child, they will instantly shut the FUCK up and wont annoy you.
It essentially means you have you lost your mind? or it can be used to express your hatred or dislike for a particular activity or person, similar to kms.