Just a brief idea before I forget:
going along the lines of Maokai, a tree brought to life by uncontrolled magic, I'd propose a champion who was formerly a minion but was hit with so many spells simultaneously that he became aware of his own existence. And he ran like mad back to the fountain before a puzzled champion could finish him off.
I'm not good a LoL speak, so forgive my rough idea. His passive will be to empower all nearby minions' attack damage by 5 (+0.4 per level) within a range of 500, but won't apply to champs.
His gameplay could be like Nidalee; he can switch between a ranged and a melee. But he starts off as melee, kind of taking the appearance of a super minion.
- ability 1: target an enemy and cause all nearby minions within a range of 700 to attack the target.
- ability 2: Posse. target two minions to follow you for 15 seconds, The minions's movement speed is made to match the champion; they attack whoever the champ attacks. After the effect, they join the nearest group of minions, but their movement speed buff is removed.
- ability 3: greater good. Consume an ally minion to regain health.
-ultimate: upgrade to cannon minion, and gain temporary attack speed buff as a result of switching (nearby minions receive half the buff). Can use ultimate again to switch back to melee mode and still gain the AD buff.