Sea urchin stings can be painful and can lead to infection. They are not usually dangerous, but a few species have a toxin that can have fatal consequences. First aid steps include removing the …

: https://www.medicalnewstoday.com/articles/319360.php

Sea Urchin The sea urchin is found across the ocean floors worldwide, but rarely in the colder, polar regions.Sea urchins are commonly found along the rocky ocean floor in both shallow and deeper water and sea urchins are also commonly found inhabiting coral reefs. There are nearly 200 different species of recognised sea urchin, that come in all shapes and sizes.

: https://a-z-animals.com/animals/sea-urchin/

A sea urchin has two defense systems. One is always engaged because it’s the natural, external body. This is made up of long, venomous spikes that are sharp enough to puncture skin.

: https://www.healthline.com/health/sea-urchin-sting

The North American river otter (Lontra canadensis), also known as the northern river otter or the common otter, is a semiaquatic mammal endemic to the North American continent found in and along its waterways and coasts. An adult North American river otter can weigh between 5.0 and 14 kg (11.0 and 30.9 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur.

: https://en.wikipedia.org/wiki/North_American_river_otter

With long, sleek, streamlined bodies and webbed feet, otters are born swimmers. They are found in waterways on every continent except Australia and Antarctica. They are often seen floating on …

: https://www.livescience.com/55090-otter-facts.html