You couldn’t tell by looking at its slender, rather frail frame, but the needlefish is one of the world’s most dangerous fish to humans, with multiple cases of injuries and even fatalities reported throughout the years.

A member of the family Belonidae, the needlefish is a piscivorous species whose most distinctive feature is the long, narrow beak filled full of sharp, saw-like teeth. But it’s not the teeth that should worry you – they’re only used to catch smaller fish – but the combination of an extremely pointy beak and incredible speed. Needlefish swim close to the surface of the water and like to jump over obstacles like shallow boats rather than go around them. The problem is that they jump at speeds of up to 60km/h (37mph), and since their obstacles sometimes happen to be humans out at sea, they literally impale them with their long beak, causing serious, sometimes fatal injuries.

Needlefish aren’t dangerous to humans because they are aggressive, their tendency to fly out of the water at high speeds is merely a natural response to obstacles in their way or to various stimuli, like bright lights during the night. Night fisherman and divers in areas across the Pacific Ocean have suffered “attacks” from schools of needlefish jumping towards a source of light.

When “stabbing” their human victims, needlefish cause deep puncture wounds, sometimes lodging themselves in their victims, or, even worse, breaking off in them. Although you wouldn’t think of comparing them to sharks in terms of danger, to Pacific Islander communities they represent an even greater risk than sharks, as members of these communities spend a lot of time around shallow reefs, fishing in low boats.

Although needlefish “attacks” are not frequent, there have been dozens of reports of such incidents over the years, including one last year, when an Indonesian boy on a fishing trip was stabbed through the neck by a needlefish. Luckily, he was taken to a hospital and survived, but some reported cases have been fatal. For example, in 2018, a needlefish was responsible for the death of a Thai Navy special forces cadet.

A rather unusual needlefish attack occurred in 2014 when a Russian tourist in Vietnam was nearly killed by a needlefish that jumped out of the water, bit her neck, and left pieces of its sharp teeth inside her spinal cord, paralyzing her. Needlefish usually spear their victims, so this case was considered out of the ordinary.

So if you’re ever in waters that needlefish call home and see a school of them swimming nearby, either leave the area or be extremely careful, as you never know when a live spear could jump out of the water at you.