Both dolphins and shimmerfish often appear in open waters, making their characteristic arched bounds, frequently before the bow waves of ships. A group of four or more shimmerfish acts as a magical lure. A victim who sees a group of shimmerfish using their lure must make a successful saving throw vs. spell or become entranced. The victim will jump into the water to retrieve the treasure unless forcibly restrained. Once the victim is in the water, the shimmerfish will close in for the kill, biting with their hundreds of razor-sharp teeth.
New mariners have the most difficulty.
If it becomes clear that their attempts at luring are ineffective, shimmerfish will ram small boats. Each shimmerfish in the group will ram the boat at high speed, one after the other. Shimmerfish can also leap up to 6' in the air to knock victims into the water. The shimmerfish must roll to hit, and then the victim must make a successful saving throw vs. paralysation or get knocked into the water. Shimmerfish love to prolong a victim's death, teasing, drawing out the terror.