Little man on bottom right corner.

[Rich kitchen]

Went to accessobility. Then to recommended for yoy. Then to setting, turn off extra dim shortcut. He disappeared. 

[Beershark]

You can actually add many accessibility functions there... Quite useful for some at time, like authenticator, read aloud etc.

Was very annoying when it just turned up, took a while for me to find out how to remove.