this is hilarious since i've set my alarm to that same tune and i, too, nearly jumped out of my skin in the morning.
it did wake me up efficiently, though.
It's a bit of an Internet meme. Basically, people have taken death scenes from a movie or TV show, and replaced the music with this song. Some notable examples are Boromir at the end of The Fellowship of the Ring, the Persian messenger who is kicked down the pit in 300, and *SPOILER ALERT* Ygritte in season 3 of Game of Thrones.
the song Jason samples (which contains the original watcha say hook) is Hide and seek by Imogen heap. I personally like Jason's better but just something to keep in mind.
it did wake me up efficiently, though.