$ sudo apt-get remove fl-cow 

Uninstall fl-cow including dependent package

If you would like to remove fl-cow and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove fl-cow 

Use Purging fl-cow

If you use with purge options to fl-cow package all the configuration and dependent packages will be removed.

$ sudo apt-get purge fl-cow 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove fl-cow 

See Also,