Python 2: True/False literal
In Python 2 (tested 2.7.15+ on Debian), the boolean operators True and False are in fact not literals, and can be reassigned. Unfortunately, I can't remember where I found this, but I've used it a few times to mess with people's code. Good fun :)
>>> True True >>> False False >>> True == False False # as expected! >>> True = False # Note, only 1 '='. This is assignment! >>> True False # !! >>> True == False # normally, False. Now, we're expecting... True
The reverse is also possible:
>>> False = True # assignment, not equality check >>> if False: print("Hello World!") # this should never work. ... Hello World!
Unfortunately, this behavior was removed in Python 3 by setting True and False to be literals. I can't seem to find this alluded to in the list; let me know if it's worthy of a PR.