I tried to make it a stencil, but I ended up with a mask, and then I liked it too much and glued it into my journal. So, here's the perfect solution: I made it into a stamp!
Drew right on the rubber with a number 2 pencil:
It's not Speedball rubber, it's from Blick's and it doesn't have a brand. It wasn't even packaged, just sold exactly like this.
Then I carved with my #1 tip:
And finished up with the #4:
Then I stamped it in my journal with StazOn so it won't smear when I paint over it:
I don't know why, but I find stamp carving freakishly fun.