You have unlimited access to all of the world's information. Source code, books, electronic information, monuments with text on them, tattoos with text, you name it. If it has information encoded has text, you can manipulate it without detection or interference.
You are trying to wreak havoc. The problem is, you can only make one small (1 character) change to only 1 thing.
What will you do to create maximum destruction, measured in terms of:
Note: If you so choose to modify source code of any kind, you can recompile the code as well (without anyone noticing).