The stunfinn's organs produced a powerful electric discharge to stun its prey.
In 23 BBY, bounty hunter Jango Fett was confronted by a stunfinn that had been strategically positioned by Rigorra the Hutt in the warlord's hazardous subterranean "Impromptu Semiannual Balmorra Death Run" competition. While Fett was sure his flight suit would protect him from such a shock as the stunfinn might produce, he was more concerned about the effect an electrical discharge might have on his helmet's sensors. Notwithstanding, Fett was able to jaw-wound the creature with a gauntlet dart before it could inflict any damage.