World War 1 let cruelty and fear flourish. This is expressed through the weapons that were used to kill the enemy. Here are my picks for some of the scariest weapons invented in World War 1.GasFirst invented by the Germans in 1915, it had the ability to kill and maim soldiers with deadly effectiveness.Mustard gas and chlorine gas were some of the deadliest gasses used in the First World War. Gas would either make your eyes itchy or kill you outright. Gas was then adopted by both sides and this deadly substance became normal on the western front. New poison gas mixtures were concocted to penetrate gas masks and kill soldiers with extreme prejudice.The machine gunThese nasty bugers could fire 500 rounds per minute. These would mow down troops at an alarming rate.The tankTanks at first were very ineffective but still very scary.This tank (Mark V) packed 2 6 pounder guns and 2 Hotchkiss machine guns. A weapon built to kill. It could cross trenches and cause chaos in enemy lines. German soldiers were shocked to see this 30 ton monster lumbering towards them.