Dusty, lunging: "Grrrrr... Ruffruffruff..."
Me, actually looking because although this dog chases deer and squirrels and rabbits and birds, he is usually silent: "Dusty, that's a skunk! What are you thinking? Run!"
I pulled that leash with vigor, turned both our tails, and RAN. Luckily said skunk had not yet lifted its tail.
We had a very short walk that day.