A Brazilian spider delivers more than a painful bite that sends most victims to the hospital. Its venom stimulates an hours-long erection.

In Brazil, emergency room staff can immediately spot the victims of a bite from the Brazilian wandering spider (Phoneutria nigriventer). Patients sport an uncomfortable erection.

“The erection is a side effect that everybody who gets stung by this spider will experience along with the pain and discomfort,” said study team member Romulo Leite of the Medical College of Georgia. “We’re hoping eventually this will end up in the development of real drugs for the treatment of erectile dysfunction.”