These fish live in the Amazon River and are frightening not because of their size, but because of the fact that they invade the gills of larger fish, usually to feed on blood, and are known for attaching themselves to the human urethra (the tube that connects the bladder to the outside of the body).

If you walk in the sea, avoid sea urchins on the sea floor because they can cause painful wounds. In particular, flower sea urchins may look beautiful but they have very sharp spines that can inject poisonous venom into the skin, causing painful and even potentially fatal injuries. Stay away from them and do not touch them.