One can use Unicode combining characters to produce an almost empty display name.
Try it yourself:
const textarea = document.querySelector('textarea');
Select all and copy in the ...
There's no clickable area to this post from the 10k tools' Delete Votes page (there's an answer here with a pending delete vote).
Even on posts I'm unable to vote to delete/undelete, I can still click the link to hop to that post from this entry.
Not super unique (I mean, we already know the title is unclickable) but I see other answers documenting places ...
As rene said, both questions and answers are posts. They are stored in the same table, so the ids are effectively coming from the same pool of numbers. In your example, the question is a post with id 4 and the answer is a post with id 7.
I can also use this method to screw up my "About Me" section, e.g., remove the text "Your about me is currently blank", and the "Apparently this user prefers to keep an air of mystery about them" that y'all see:
Go take a look in my profile.
As we can not see, I was able to submit an empty question.
To reproduce it:
Submit a question with a content
Right after the submission, edit the question to remove everything and include invisible zero-width spaces.
Edit the below snippet to be able to see the spaces (they will show as red dots if you are using Chrome)