People have tried to use everything imaginable as a weapon, but the most effective weapons are honed until man can kill, maim or destroy with the least amount of effort.
This deadly factor is the key to a weapon being considered highly effective, but it also makes it easy to tell when a weapon literally can't cut the mustard.
But before double-barreled cannons or dogs carrying anti-tank mines can be declared ineffective they must be tested, and weapon testing is often a deadly business.
This animated history lesson from Second Thought walks you through some of the worst weapons ever devised, like the ridiculous looking Tsar Tank, the big wheeled joke of WWI.
-Via Laughing Squid