Using Impossible Target Numbers?

    In Pathfinder there is the "aid another" action, which lets you give an ally a +2 on a roll.  This is not a huge benefit, though under the right circumstances it might be a critical difference.  Still, on average there is not much use to this action.  In the 5th Edition SRD I've been going over, the Bard has the ability to give a bonus d6 to an ally's roll.  This can potentially be a little better than the option in Pathfinder, but on average it's still not a world shaking option.

    My thought is this: why not set impossible target numbers, like a 32 AC at 1st level, and then let the players add their rolls together?

    This feels like an option worth thinking about for a few reasons.  First, if you tell the players (maybe after the first person tries something) that the target number is so high, then they will know (without a doubt and hopefully with a little fear) that this is a special "boss" monster/ circumstance.  Using such over-the-top numbers says that this is a group challenge, something impossible for a single player to accomplish.  Heck, you could even say the monster has an impossible to-hit, like they have a +20 to-hit, and so a player standing alone will be hit every turn without fail (now that's a dragon).
    Second, you can stretch the rules with this to encourage outside the box thinking.  Okay, let's take that dragon above, with the +20 to hit the 1st level players.  Well, we'll let any assisting player add his roll, so if the thief jumps on the dragon's back and starts climbing it, we'll reduce the dragon's to-hit by the thief's climb check - since the thief is distracting the dragon by climbing it.  Or maybe we'll let the bard make a perform check to create a distraction, and subtract that from the dragon's attack, also giving the fighter a, well, fighting chance to survive.
    Third, mechanically this is really easy.  Straight addition with clear target numbers should be pretty easy for the players or GM to work out the odds.  A simple mechanic can hopefully make it easier to focus on the narrative and planning.  You can tweak it lots of ways too, like letting all the PCs in a group divide the damage among themselves from a big attack like a dragon or giant - even a fireball (did one PC "jump in front" of it to shield the others?).  All you have to do is take a number that would be the total of however many players you have (or are involved) - you make the PCs figure out how to divide that.

    Sadly, I have no party to test out this idea, but it's been hovering around the back of my head for a while; so I thought I'd throw it out there for anybody brave enough (or crazy?) to give it a try in their game.  If you do, drop a comment below (or on Twitter) and let me know.