>>318025a) 1 person with the power over a weapon of mass destruction so big that it can wipe out earth (with blast or disease)
b) planetary shifting of the pols which would let solar flares and such zap us
c) meteorstrike
d) aliens who are pissed off
e) science getting too powerful and underestimating their creations
f) sentient robots who just wanted one day off
g) somebody stops the simulation
h) /bant/
We can do it if we try!