Drowned shots trident with fishing rod

when you swim past a drowned, who holds a trident in his hand, If he shoots the trident once, he gets a fishing rod in his hand. But when I get closer, he shoots trident projectiles with his fishing rod. I don't get the trident though, only the fishing rod if I kill him. In the picture you can see the projectile flying towards me and the fishing rod in his hand.