pip how to remove incorrectly installed package with a leading dash: "-pkgname"

After running pip freeze I noticed the following warning on top of the list:

WARNING: Could not parse requirement: -atplotlib

So I checked the installed packages using pip list, and indeed the following is considered a package:

Package         Version
--------------- -------
-atplotlib      3.0.3

I assume I probably had a typo when installing/upgrading matplotlib, which led to the aforementioned "package" being installed.

But I am not able to remove it as pip uninstall -atplotlib is read as a command and returns the following error:

No such option: -a

I found the following folders:

C:\Users\name\Anaconda3\Lib\site-packages\~atplotlib

C:\Users\name\Anaconda3\Lib\site-packages\~atplotlib-3.0.3-py3.7.egg-info

Is it safe, and sufficient, to remove them?

It is safe to delete the offending folder(s) from your site-packages directory.

More info below (source):

When uninstalling a package, pip will now rename it in place to a name that cannot be imported, and once it has confirmed that everything will succeed (including installing new versions if it’s doing an upgrade), only then will it delete those folders. If something fails, it renames them back.

Previously, it would copy the entire contents to another directory, and potentially another drive, and then copy them back if it needed. So this change is a significant performance improvement, especially for packages with a lot of files in them.

What you’re seeing here is that the deletion failed for some reason - perhaps pip crashed? - and so the directories were not removed. I thought pip ignored them completely, but perhaps something else changed since I tested that?

The directories are safe to delete.

EDIT: According to this link, provided by Lawrence in his answer

looking for and deleting the incorrectly named folders in your site-package directory should solve the issue.

If this is not sufficient, continue the cleaning as explained below.

Searching for the name of the broken package (without the leading dash) allowed me to find the following two folders:

C:\Users\name\Anaconda3\Lib\site-packages~atplotlib

C:\Users\name\Anaconda3\Lib\site-packages~atplotlib-3.0.3-py3.7.egg-info

Following Hoefling's comment (below)

I checked the SOURCES.txt file in the egg-info directory %dir%/~atplotlib-3.0.3-py3.7.egg-info/SOURCES.txt. Went through the list of paths in this file and made sure all paths listed did not contained ~. Then I renamed the directory ~atplotlib-3.0.3-py3.7.egg-info into atplotlib-3.0.3-py3.7.egg-info (removed the tilde ~).
Finally, I ran pip uninstall atplotlib, which prompted the following:

Uninstalling atplotlib-3.0.3:
Would remove:
C:\Users\name\Anaconda3\Lib\site-packages\atplotlib-3.0.3-py3.7.egg-info C:\Users\name\Anaconda3\Lib\site-packages\matplotlib
C:\Users\name\Anaconda3\Lib\site-packages\pylab.py

Proceeding with the removal solved the issue (the warning disappeared and the package is not anymore on the package list.