DAYUM is a dangerous weapon created by the legendary Darth Vader.
Darth Vader's first act as an evil overlord was to track down Ron, one of his worst enemies ever. He tracked down Ron as he promised, and commanded him to bow to his might. Ron refused.
Darth Vader spent three years working on his weapon, and another year testing it (it would have taken five seconds to use The Force, but this didn't occur to him). He then tracked down Ron again, and used the weapon.
To use it, one must play the Benny Hill theme song and say "DAYUM" out loud. Then, the world will explode. It is very effective at killing enemies, damaging property, and nullifying everyone's insurance.