Hamish MacInnes. Older Scottish climbers like WH Murray had shortened ice axes for easier chopping, or even used a slater's pick, but MacInnes was the first to really investigate the properties of the spike.
"The Message" was his first ice tool, invented for personal use, with a heavy hammerhead and steel spike, in... yes it was... 1940.
Same guy later took the steeply dropped pick and came up with the Terrordactyl.