A Mammal with Electrical Defenses

I'd like to create a land-based mammal that uses its electricity NOT for navigation or hunting, but only as a defense (enough to stun creatures approximately its own size or marginally larger, without killing them).

The proposed characteristics of my creature:

• it is 2 feet in height (at the shoulder) and a faculative scavenger and small-creature predator (though it doesn't use its electrical discharge when hunting)
• it discharges electricity with modified muscle tissue surrounding ONLY its back (similar to that of an electric catfish)
• it directs the electricity to its hair which scrapes a bit of charge into static electricity: some of it sticks to the hair, some of it could shed into ionized air. When it discharges electricity, sparks and a crackling sound are produced.

Are there other important characteristics? Is there anything contradictory in what I've already proposed?

• The some of it could shed into ionized air is impossible without a insulator skin or exoskeleton. The moment the air is ionized, it will go to discharge in whichever provider of the opposite charge. Even with an insulator skin, ionizing air is simply a loss of energy - at the best, a transient episode like that may be used as a warning. – Adrian Colomitchi Mar 16 '20 at 9:03
• See also corona discharge - nothing to do with COVID-19. – Adrian Colomitchi Mar 16 '20 at 9:09
• your big problem is unlike water air is a really good insulator so it will have to make contact with something to shock it. – John Mar 16 '20 at 9:47
• @John water is a very good insulator, too. It's the impurities in it (like salt) that conduct electricity. – infinitezero Mar 16 '20 at 12:56