The skunk sprayed Mr. Porter for falling on his home (the tree stump) in "Pups Save a Surprise". This, being a method of self-defense, is a common trait among skunks.
The skunk tends to not like Mr. Porter since he fell in the stump blocking his home. Even when Mr. Porter is free, the skunk still sprayed him. He liked the peanuts Rocky fed him while the PAW Patrol freed Mr. Porter.
The skunk has a gray body, two white stripes on his back and a white underbelly. He also has brown eyes.