Easy way to kill spidey--yet it was overlooked

Most of the villains who have gone against Spiderman have stood no chance strength-wise... Well I was sitting and thinking and it occurred to me: all a villain needs to do is get bitten by the same radioactive spider that bit Peter and, theoretically, they should be granted the same powers as him! After the spider bit Peter it's not like it died or anything---and there were like 3 others so why don't they just go to that lab and get bit? And the scientists who created the spiders---shouldn't they have known that that's how Spiderman got his powers? Come on Marvel, I love you to death but make more solid stories!