new game mode idea

So what do you-all think about a new game mode on summoners rift where it starts of normaly exept that baron nashor will summon when all other monsters spawn. When the baron nashor is killed, after his death it pops up a cool cinematic video that explains what is happening and after the video is done everyone is back in their spawn and the real baron nashor has spawn and he is the size of one lane and both teams need to fight toghether to bring him done.

some more explanation:

The team with most kills before they get on the same team to cooperate will get more experience and influence points.

After the cinematic everyone is on the same team and no friendly fire.

For compleating the game mode that is very hard you will get special rewards like: riot points, special baron nashor skins, summenor icons...

Thanks for reading and please comment some more ideas or questions.