I did a pretty bad job delineating this one (lots of ghost lines)---should have just drawn it with a dark pencil to begin with. :p
Anyway...
I could be very wrong, though I believe my last remaining, recurrent (ie., used more than four times) OC that had yet to be depicted in One-Cent ACO form, was the skunk ...and now she has been. ^^
'The skunk' isn't a name like 'The Dog', it's just the skunk doesn't have a proper name (and shouldn't). ^^
At the time, Timmy had no face, and therefore no nose. This was of interest to the skunk, who was desperate for a mate (without a nose, Timmy couldn't smell her---moreover, the skunk believed that without a nose, Timmy wouldn't be attractive to anyone else).
Timmy, of course, didn't need the skunk---more importantly, he thought her judgmental and rude. And so it was the skunk was never successful is capturing Timmy (at least not for very long).
The skunk has a mate now, but will it last? We may never know! D:
Also, I was asked this years ago, but somehow missed the question---the skunk is gray and white. However, due to how I had my scanner set up waaaaaay back in the day, the skunk could sometimes look purple. I dunno how that happened, it just did. :p
...Pencil.
Nothing special about the featured pencil other than its 'traffic signal' ferrule. The barrel is round, and the ferrule is square (very similar to those 'Broadway' and 'Fifth Ave' pencils, respectively). This particular pencil was sold/given away (?) by Jolley Oil Company. I'm unsure of its vintage, though given the presence of alligatoring, the paint is obviously lead-based. So, the pencil was (very likely) made before 1978.
This pencil seemed a good choice for the skunk, because the skunk didn't know when to stop ...ok, I'm not funny. :P
Also, like the skunk, this pencil has a tragic history...