Hold down Ctrl and Alt and press t (Ctrl Alt + t)
Copy/Paste (or type) in to your terminal -
Enter your password when asked.
sudo apt-get install cmatrix
Once installed if you copy/paste (or type) in to your terminal -
cmatrix
An animated matrix image scrolls downwards filling the terminal.
I made an example with SimpleScreenRecorder
Hold down Ctrl and press C (Ctrl+C) to exit back to your work in terminal.
I think it can be useful to stop people looking in your terminal, such as at your newly made random passwords whilst you are busy making some tea.