Why I can't learn underworld leech

I bought underworld leech because it said physical monster can learn this skill, after I bought it, I try to give it to Boarbarian... But it said I can't learn it.... So disappointed after took lot of time to collect the blue orb to buy this skill... Please fix this bug. So my Boarbarian can learn this skill. Thanks

You're new aren't you?

Boarbarian can't learn any moves (well supposedly he can learn a couple new ones now but only like 2-3 and to the best of my knowledge that's not one of em). And besides, even if he could learn that move teaching a magical move to a physical monster is the worst thing someone can do, teach it to a psychic or ghost type if you can, it'll do a lot more good.