I liberated the summary from Charlie Stross over at Making Light. Anyway, the topic was poisons and got into some esoteric stuff. And being a nerd, I went to the linked site and spent an appalled hour reading about some reagents I was blessed to never have worked with (the nastiest I had was a toxin and a teratogen).
Anyway, imagine overriding the safeties on a replicator and then putting it on a timer for some of these. Whee!