Add this to your .bashrc:
clippy() { echo "I see you're trying to use the terminal …"; echo " v "; echo " ╭─╮"; echo " ⌾ ⌾"; echo " │▕│"; echo " ╰─╯"; }
function command_not_found_handle { clippy $1; }
It will result in:
$ adsf I see you're trying to use the terminal … v ╭─╮ ⌾ ⌾ │▕│ ╰─╯
Looks better in the terminal.