Rule 63C is an addition to Rule 63 stating that if there is not rule 63 of a character, and a "63" of them is not currently in production, it is your job to create a "63" of them by any means possible.
Anon: Man, character
is so kickass. I wonder if that means their female counter-part is totally hot.
me: Look up thier rule 63 on teh intertubes.
Anon: *gasp* There's none!
me: Then it's Rule 63c, we gotta make some 63 of character