Well, something went horribly wrong. It took about half a second for it to tear through the stupid fence and 5 seconds to KO me from full health.

Is the wiki wrong? Maybe this was some super fox, like how occasionally I come across super ants that go faster than run speed. This thing did seem particularly strong I suppose, I hit it with 8 or 9 good 20 damage sling shots later after following it to a cliff that I could cheese it with, and it didn't even run away at all during that time.
(I'm really pissed too because I ran out of rocks, and before I could run back it de-aggroed on me, saw a bunny, and ran off into nowhere and I didn't even get the damn thing after that entire ordeal!)