He is best known for creating the Spider-Slayers, robots designed specifically to hunt down, capture, or kill the web-slinger.
Spencer Smythe and the Spider-Slayers first appeared in The Amazing Spider-Man #25 (June 1965), and were created by writer Stan Lee and artist Steve Ditko.
[3][4] But his creations, no matter how deadly or powerful he made, were always defeated by Spider-Man utilizing a key flaw in their designs.
[5] Eventually, Smythe is fatally poisoned by the radioactive materials used in the robots' manufacturing and attempts to kill Spider-Man and Jameson with a bomb.
[11] Spencer Smythe is quite intelligent, capable of designing advanced robots that could pursue solitary targets.