Go to your Admin Console and type the following:
Do the same for these:
ETA: Adding also carambas4389210
Apparently these people are commenting with spoilers on unsuspecting journals, so if you fear being spoiled, banning them from commenting is a good option.
If you run an HP community (or a community with a large number of HP fans) and want to prevent them from being spoiled, put this in the Admin Console:
ban_set wasteofpages from communitynamehere
These people have already been banned from this community, and if anyone catches wind of more usernames, please let me know!
ETA: I've also gone ahead and made commenting Members Only, with Moderated Membership. I'm not letting us get spoiled LOL. If you have been an active part of this community but you had never joined as a member, do so now. I'll be accepting new members as long as I can tell you've been here longer than a few days.
Another edit: You may also want to turn off Anonymous comments on your journal! To do that go to Manage Comment Settings and set it so only registered users can comment!