I think that there should be heroes that can be summoned when enough coins and/or donuts are accumulated in a pot. If the "Super Hero" is summoned then everyone attacking the villain will be taken to an animation screen where they will watch the super hero face off against the villain. The reward should be the amount of damage the super hero has done divided by how much you have donated to the pot.
I think that there should be multiple heroes all of which would have different styles of attack and would have different strengths/weaknesses against different villains.
I also think that the super heroes shouldn't be anything near an instant win and should be relatively cheap because I also think that you should be able to use the heroes in different order to get combo effects and the such. This works better in the kong server because there is a global chat and everyone would be able to organize well.