No. The C++ Mascot is not a "diseased rat named Keith" drawn by RMS.

This is the article: https://lunduke.locals.com/post/5111104/no-the-c-mascot-is-not-a-diseased-rat-named-keith

This video version: https://lunduke.locals.com/post/5180325/no-the-c-mascot-is-not-a-diseased-rat-named-keith-drawn-by-rms