I acquire the services of all of the world's scientists. I get them all to focus on the creation on a trans dimensional device, which allows the user to visit alternate dimensions . Using this device I spend a number of years attempting to find an alternate reality where someone had invented time travel. Luckily there is one. I steal the time machine technology from this dimension and return it to ours.
After firing all of the scientists for complaining that I had not just asked them to invent a time machine - I use the time machine to go back in time to just before my very life like cardboard cutout of a man holding a gun is stolen and repurposed as something to help debug Glaurung's advanced PROGRAMS. I destroy the time machine, lest it be used for evil. I then draw a comical twirly moustache and pair of glasses on the cutout man.
Upon attempting to use it to help with his PROGRAMS, Glaurung finds it oddly amusing. This amusement causes him to make a mistake in his PROGRAMS. He then is forced to spend the time he was going to be spending discovering undefended hills, instead fixing the bug in his PROGRAMS.
My hill.