Stellaris observe command

This command switches you to observer mode. Use the play command to revert control. Note that if the game is unpaused in observer mode the AI will take control of the player empire.
Command syntax
How to open the console in Stellaris
Press the ~ / ` key to open the command console. This key is located at the top left of the keyboard, usually under the F1 or ESC key. Type the command and press the Enter key.