Train both pets to adult and then hatch them together a couple of times. That way you can end up with a stronger Frankenbunny.
You'll get a mix of the Sea Dragon's strong stats plus useful talents like Spritely (may cast Sprite), Spell Proof (10% universal resistance) Pain Giver (6% universal damage), and Sharp Shot (6% universal accuracy), plus the Storm-specific talents of the Frankenbunny.