Phoneutria nigriventer is a species of medically-significant spider in the family Ctenidae, found in the Southern Cone of South America (Brazil, Uruguay, Paraguay, and Argentina).

[4] They are nocturnal, and actively hunt at night, killing by ambush rather than using a web; during the day, they are found hidden under logs or crevices.

[7] The bite of P. nigriventer in humans, can cause several symptoms such as priapism, tachycardia, arrhythmias, cardiogenic shock, acute pulmonary edema and convulsions.

At deadly concentrations, these neurotoxins cause loss of muscle control and breathing problems, resulting in paralysis and eventual asphyxiation.

This sensory nerve stimulation causes a cascading release of neuropeptides such as substance P, which triggers inflammation and pain.

[23] A 23-year-old market worker was bitten on his hand in São Paulo, Brazil, while moving a bunch of bananas.

The victim additionally reported pain radiating to his chest, increased heart rate, dizziness, nausea, coldness, drooling, vomiting, and an immediate erection.

Immediately after the bite, he experienced severe local pain, blurred vision, profuse sweating, and vomiting.

Four hours after the bite, his heart rate reached 150 beats / min, and he also experienced mild tachypnea, cold extremities, profuse sweating, generalized tremors, and priapism.