In Fen Zaam (Master; Will; Slave)
Take possession of your enemy and use his body to fight.
By using this shout, you take control over one enemy and you can fight in his body for 30 seconds or until the body is defeated. After "leaving" the other body, you regain control over your own body, which is ethereal while you control other bodies. (Levelcapped, so you can't control every enemy.)
Hard to implement in the game, but it would be awesome
Mal Fahliil Motmah (Little Elf Slip)
Turns one enemy into a tiny bosmer that slides everywhere (Comical Shout, as per rules)
1st Part of the shout shrinks them, the 2nd turns them Bosmeri, and the 3rd makes them slip and slide everywhere as if on ice (Can't attack, block, or use spells whilst affected with the 3rd part of the shout).
This is my submission.
Arcane Shield Blast
Sahrot - Spaan - Nah (Mighty - Shield - Fury)
Erects a bubble shield around the caster that deflects all forms of physical and magical ranged attacks. Upon dissipation of the shield, an energy wave is released, draining stamina and magicka from all enemies in range.
This shout is useful for melee fighters taking on several ranged enemies at once, as it allows protection from ranged archers and mages while still allowing melee enemies to enter the shield.
Shield radius and blast radius increase as more words are shouted.