Water Elemental:

Hp: 20
Attack: 1d20 water dmg + 1d6 drowning dmg next round
Defense: -1 dmg, -5 mag dmg
Immunities: Water and Magic Circles of Magic and Swords and Axes.
Abilities: Tidal Wave (Replenishes Caster for 1d20 hp, while hitting enemy for 3d8hp, this kills the Elemental also)