"Evil" Plugins
R_J
Admin
I know there are some things which wouldn't be good for a community. Mobbing members might be fun for the rest of the board, but it is noticed from outside and who wants to be the new one in a shark basin? No one, therefore soon there will be only some bored sharks left.
So no, mobbing isn't good, it's evil. But we all know how much fun it is to be evil... 
Just for fun, let's assume you wanted to allow your users to be super assholes to each other on your forum: which plugins would you like to have for that?
I could think of the following:
NameFinder:
Description: Allow other users (but not the user himself) to change the title of a user. (A history in the profile would be nice)
TrueColors
Description: Each user can suggest an avatar for himself or others. Community can vote which one should be used and the one with the most votes would be the current avatar.
FreeSpeech
Description: Allows up- and downvoting posts. Increase/Reduce allowed posts per day based on votes.
ToWhomItMayConcern
Description: Allow discussion authors to explicitly disallow some other users to see the content of the discussion.
And it goes without saying that all this plugins come with a popup and mail notification which cannot be switched off
What ideas could you come up with?
Comments
Sounds like great game mechanics for a fun Minecraft board or similar ("Mafia"-Series games).
These plugins show great. Can they be developed without JavaScript?
You got me all wrong!
I wouldn't write such scripts. You would have to pay me a lot of money to convince me and even if I would write one of those, I would use an alias because it would feel ashamed if I did. And I would take no responsibility on the results - or the insults...
Human nature is kind of strange: while it is hard to find a person which is not nice if you ask for help, it is nearly impossible to find mercy in an anonymous crowd.
Giving your community the tools to anonymously act insulting and making fun of others, is really no good idea.
FreeSpeech
Do not take this as criticism, just my opinions.
Not once watched as plus or minus led to confusion. always looked like a "tug of war" on both sides. Perhaps it would be useful to offer users support the author, pushing it to the top responses that brought real benefits from their own questions, the best are at the top and others can compete for this right.
If I understand your idea
The Full Astley
On every page load, one random navigation link on the page becomes a RickRoll.
Googlish
A post is taken through several iterations of Google translate, using random languages, before being re-translated back into the original language.
So
ends up
Never gonna give you up, never gonna let you down...
Thanks for that...
Wrong Window
10% chance your reply is assigned to a different recent discussion than the one you're in.
Mirror Mirror
Horizontally flips every image attachment.
Snow Storm
Incrementally sets the color of every element closer to white based on the number of users online.
Based on each click the user makes.