Elemental Form
You target a square in melee range and 'merge with it' (similar to Summon Elemental) and you take the form of an elemental [Fire, Water, Air, Earth]
Each form gains an enhancers, an immunity, a brand, a weakness and retaliation on bad hits:
Fire: fire enhancers, fire immunity, ice vulnerability, flaming UC, inner flame style explosion on severe hit.
Water: ice enhancers, ice immunity, fire vulnerability, engulf auxilliary, bleed steam on severe hit.
Air: air enhancer, electricity immunity, wind vulnerability, electrocution UC, Chain lightning-style beam on severe hit.
Earth: earth enhancer, AC boost, LRD vulnerability, pure boost to all melee (vorpal), explosion of metal fragments on severe hit.
Also all share a passive (may use HP for MP (for spells of the associated element only), rSticky and negative energy vulnerability).
I will admit that some of these overlap some with existing Transmutations, but there are no fire or air forms at all right now and the water effect is also semi-unique.