Bandwagon is a logical fallacy, a propaganda technique used to convince people of an idea. It is a fallacy because it's not true. If you have ever heard the phrase "jumping on the bandwagon" it means going along with what everyone else is doing. Basically, bandwagon means: everyone is doing it, so you should to or you'll be left out! Bandwagon can be used to manipulate people, because we all naturally desire to be part of the hottest trend or to do what others are doing.
One use of bandwagon is the idea that some animals are sacrificing, so everyone should sacrifice. This is often used during rebellions. Bandwagon can be used to encourage everyone to do their part and contribute, because everyone else is. The cows give their milk, the chickens give their eggs, and so on. Other examples of bandwagon are the battles and the windmill. Everyone wants to be involved, because they don't want to be the only ones left out.