The Unicode null character, , which often terminates a null-terminated string. Its mere presence in a string (outside the end) will always cause software bugs. I tried to include the character itself (faulty PDF OCR from an underlined “가”, confirmed through a Unicode converter), but it would always cause UD to error (obviously).
I used empty brackets because I tried to insert the actual character, but Urban Dictionary would always
This character U+0000 is impossible to get into a string, and if inserted into a URL by %00, can unlock a security vulnerability called null byte injection
Person 1: Did you see that nameless character in Among Us?
Person 2: Yeah, he was using this character: " ", it's like an invisible character.
Person 1: You just typed two spaces, that's not an invisible character!
Person 2: Just google " " U+3164.
" " (U+3164) is a blank filler code that is invisible, and can be used in places the space key can't. most places where you can name yourself you can't use just spaces, so this works for an invisible name or almost any other reason. if you are not able to use it in a place, put periods or another symbol on each side of the ' ' and it will usually work.