A MGX GUI (short for Maintenance GUI) is a GUI that a Roblox user adds to their own game. The purpose of an MGX Gui is to phish somebody else's account password by sharing them.
Description
The MGX GUI is a sort of Game UI that looks like a recreated version of the web login screen, with the most possible visual exception being a slightly different font. The login screen says that there is a maintenance undergoing and asking their login information. If the user types their login information, they will be shared using webhooks. Some versions of these GUIs also say that the user had been signed out.
MGX7 GUI
An MGX7 GUI is an MGX GUI that is injected into other users' experience servers using a level 7 exploit instead of being inserted into their own experience through Roblox Studio. These GUIs are considered more "dangerous" as they can easily target more people.
Staying safe
You shouldn't fall for these scams and enter your password as this won't give the promised items to your account. Getting scammed from MGX GUIs is very easy as all you have to do is enter your password. Many versions of MGX GUIs threaten to kick you out of the game after a set time or to permanently ban you. However, there is no reason to be scared because the worst they can do is trello ban you out of a server. To avoid being kicked out, you can enter a fake password to make the GUI disappear, but most of these GUIs have now been updated with a password checker so they are more convincing, but you shouldn't fall for any login GUI in a Roblox game. If you do fall for one of these scams, change your password. The scammer won't be able to get into the account.