What kind of magic do you like?

And if you also happen to have the Martyr spell (Magic of Life, level 2), then Hypnosis + Martyr is a real treat, or you can hypnotize an enemy hero.

And even better is hypnosis + sacrifice (it's hard to level up, but if you manage to...), sacrifice a group of enemy units and resurrect your own.

Hypnosis, DraGuNSt, can also be cast over city walls, just like poison.