Can't get it up any more? Chilean scientists are working on an even better version using... black widow spider venom.

The scientists, working at University La Frontera in the southern Chilean city of Temuco, have been studying the effects of the venom's various properties for the past seven years.
By isolating these elements, they could reproduce them synthetically in drugs to strengthen weak hearts and help men with erectile dysfunction.
Last November, they discovered by accident that one ingredient in spider venom could not only facilitate male erection in a way similar to the popular Viagra pill, but also render sperm infertile.
"This new drug could help the functioning of the male erection without having to worry about the partner getting pregnant," Fernando Romero, director of the research project, told Reuters on Wednesday outside his lab filled with the dangerous spiders caught in southern Chile.

No one seems to have noticed the irony in taking venom from a breed of spider where the female eats the male after fucking and making a male impotence tablet out of it. I'm sorry, but there is no way in hell I'm trying it.