emiT-C
A time travelling programming language
...You can kill variables, which destroys them permanantly- at least until you send another variable back in time to kill the variable doing the killing. This very quickly leads to a lot of confusion, with a constantly changing source code and the very easy possibility of creating a paradox or a time loop. Remember, the timeline doesnt reset when you go back, any changes made before will remain until you go back even further to stop them from happening.