U+0000 

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

U+0000 by iliketoshitmypants69 August 10, 2019