I would create a witch. Yes, real witch, WHICH (😂) would have low HP (let's say 2) but strong magic dmg (3) and crazy speed (like 6). That way it would be deadly but could get killed easily by magic too. And I would call it "Fragile Witch" 😁 At level 2+ she would have another special ability: put fire on attacked monster. The fire would work just like the poison does but it would be red instead of green :) The fire would take 1 hp every turn, even if our Witch dies.
What is more, the most surprising thing about her, would be her classification. I would see her in "earth" team rather than fire. Don't ask (she's a witch, who knows how and when).😝