Annihilation

Noun - 1) Complete destruction or obliteration, total defeat. 2) The conversion of matter into energy, especially the mutual conversion of a particle and an antiparticle into electromagnetic radiation.
Origin - From the Latin : to reduce to nothing - from ad: to and nihil: nothing.

They must have heard me singing.

Caution, you are in the presence of an extreme word which must be used with caution. This is not to say that you should avoid using it. No, use it often as you can. Just go careful. It must be treated with respect and should either be shouted in your best Arnie impression or whispered in the most sinister and downright evil voice you can manage. Accompany these with a loud "Noooo" or a supercilious, full-arm point (especially if you have long, pointy fingernails) and you have the perfect accompaniment.
Extra credit is given to it for having a hidden scientific meaning that I didn't know about. I have always been partial to a bit of particle and antiparticle conversion into electromagnetic radiation.

ANNIHILATION!