No, this spider's venom will not give you a permanent erection, but it might last a few hours

A supermarket in Austria was evacuated following reports of a spider whose bite can cause hours-long, painful erections. But media claims that the erections are permanent are not supported by Science.

The spider was discovered in a discount store in Krems an der Donau, 45 miles (72 kilometers) west of Vienna, and is believed to be a Brazilian wandering spider (Phoneutria nigriventer), leading to a flurry of media reports claiming that its bite could cause permanent erections.

The 4-inch (10 centimeters) spider's potent venom gives it a nasty — and occasionally, fatal — nip that increases the victim's blood pressure and causes hours-long erections. However, there is no evidence that these erections are ever permanent.

Related: What is the deadliest spider in the world?

Past studies in rats have revealed that the Brazilian wandering spider's venom works by causing nitric oxide to be released in the brain. This chemical leads to a biochemical cascade that ends in the production of an enzyme called cyclic guanosine monophosphate (cGMP), which causes the muscles in the penis to relax, enabling 10 times the blood to rush into it. 

A few hours later, however, another compound, called PDE-5, arrives to break down cGMP and return the penis to its previously limp state.

The spider's tumescent trick works from the opposite end of the biological pathway than drugs such as Viagra — which blocks the production of PDE-5 — leading scientists to study it in hopes of an application in future drugs to treat erectile dysfunction.