It'd be like a button on a user's profile that allows you to downvote all a user's posts at once (you can choose between answers and questions).
You could also choose to go into the user's All Answered and All Questions posted section and click the button for every individual page of answers or questions the user has. This keeps the convenience of not having to click on every individual post and downvoting while also allowing you to spread out your downvotes among different users, if you don't want to use up most of your points mass downvoting all of one user's posts.
To keep things fair, I imagine there's a cost for mass downvoting. I'm thinking 100 points for each page of questions/answers a user has, even if they don't have 20 questions/answers on that page. I think 100 points, while being more expensive than the 40 points it would take to go into each individual post and manually downvote it, is fair as it again adds the convenience of being able to quickly downvote, as well as being a decent wall that prevents short-term trolls from joining and clicking the button right away. 100 points also isn't that much to accumulate, if you are regularly engaging in the site.
For mass downvoting all answers or questions, I think [5 × user's # of total q/a's] is a good price, usually being less expensive for downvoting users with a higher amount amount of q/a's if you are willing to sink your points into mass downvoting them, while the (sometimes) lower cost can also serve as a slight incentive to mass downvote users on their profiles instead of just on the individual pages. This option could probably also be locked behind having 100 points.
Overall, I think this would be a great long-term addition to PokébBase as a whole. It encourages users to keep making quality posts and stay behaved so they don't risk getting downvoted, while also adding a slightly competitive aspects that shakes up the mundane life of the site from time to time.
What do you guys think?