WMD

[Tanaka Kichigai]

One (1) cosmic string:

Capable of coring any planet for the destruction of a civilization or the mining of minerals. Also capable of cutting stars, pulsars, and white holes. Must be accompanied by an appropriately sized armada of control vessels

(Don't remember the author or the name of the book where this is from, but I'll edit the post when I find it.)

[Taurec]

I think the Big Bang beats em all