Game Mode: That Was Unexpected.

So imagine this. Vel'koz is up to his shenanigans and decides he's bored with Summoners Rift and decides to step up his game. So, he does an experiment! He's been inspired but the story of Scion and Urgot, and inventors like Heimerdinger and Viktor and has decided to make abominations of his own! So he lures 10 champions into a Summoners Rift match and BAM! Smacks them with a dismorgrification beam.. At first, he's confused. Nothing seems to have happened.

But moments later, as he's re-calculating his measurements his results he discovers the success was far greater than he could have imagined! It wasn't their bodies that got scrambled, it was their minds!

All the abilities of all the champions got swapped around. Now you have Garen with a Riven Q, Ahri W, Rengar E, and Karthas R.

Some champions would need to be disabled because their abilities just wouldn't work on their own. (i.e. Karma's Matra R wouldn't work with other champions abilties. so whoever gets her R would be unlucky... Unless when Gangplank uses Karmas Mantra the allies with the rest of her abilies receive the mantra effect? Odd... but interesting.)

Anywho just a thought.

TL;DR: All champion abilities are scrambled at the beginning of the match.