This is based on a message I left for a user as an example of how people try to force characters to fit a description.
In the Pixar movie A Bug's Life, there is a bird that appears a few times and causes problems for various characters in its search for food because to it, those characters are food. I have seen other people try to classify the bird as a villain or a hero during the past two years, but it's neither. It's just a bird. It is an antagonist because it's an obstacle that Flik and the other ants have to figure a way to get around, but it is nothing more.
Here's why the bird is just an antagonist and a very minor one at that:
To be a villain, you have to not only be a bad person, but you have to go out of your way to be bad, such a really enjoying hurting the hero.
Does the bird do anything villain-like? No. It is looking for food and to it, ants are food. The best we can say about the bird is "it isn't nice that the bird tries to eat the ants", but in no way does it go out of its way to hurt the ants and enjoy doing so.
To be a hero, you have help other people in a deliberate way. Sometimes this happens as an accident, but in those cases, the character is thanked by the other characters and usually they become a better person as a result of helping others. Likewise, to be an antihero, your deliberate actions help others, but the way you do it or your reasons for doing so aren't that good. In other situations, they might even put you in the antagonist or villain category.
Does the bird do anything hero-like, even if it might look like an antihero? No. It's a bird looking for food.
This bird has also been called a "reformed villain" or a "reformed antagonist". Though it is an antagonist, you can't say it's a "reformed antagonist" because in order to reform, you have to be confronted with information that causes you to stop, think about what you've been doing, and make a conscious decision to change your behavior. And when you make that change, it has to be a permanent change. It can't be you try it for a while, then go back to doing what you were.
Does the bird reform? No. The movie does not show it making the decision that eating ants was such a bad thing that it's never going to eat ants ever again. Throughout the movie, the bird is simply searching for food.
There have also been cases where the "enemies" and "minions" lines in the Infobox have been filled in. In these cases, they are assumptions. "I didn't get what I want, therefore that other person is my enemy." People don't do that in real life. You don't say, "Our team didn't win the basketball game, therefore the other team is our enemy." A rival might be a better description, but if you go further and list them as an enemy, you are spreading hatred that you don't need to be.
Are Flik and the others the bird's enemies? No. The bird is looking for food but doesn't happen to get it at that time because they were able to escape. That doesn't make them its enemy, just like being able to capture Hopper and take him back to her chicks doesn't make Hopper her friend. In all of these cases, they are just food to the bird.
Going along with that, the bird's chicks have been called her minions. A minion is someone that will follow your orders. Does the bird give any orders to her chicks? No. They sit in the nest waiting for their mother to bring them food, like other baby birds do.
So why do people try to say this bird is a hero, antihero or a reformed villain? It's because they're trying to force the character to be those, but the reality is it's just coincidence. It's pure coincidence that the normal behavior of this bird looking for food happens to help Flik. The bird doesn't think, "I'm going to help Flik by taking Hopper away because Hopper is being mean to Flik." The bird thinks, "There's some food. I'm going to take it back to my chicks."
That's it. Its normal actions that haven't changed and have no reason to change just happen to help the hero of the story. It's not something deliberate the bird does. It's just coincidence that it helps them. Don't ascribe behaviors and motives to a character that aren't shown in the movie.