“Is this a hammerhead worm!?” asks this reader in her submission about the gray, slimy-looking worm-like creature pictured below. We actually cannot tell if it is one or two organisms, though we suppose it does not matter much. “I was horrified to find it in my toilet! Thanks.” We understand how our reader feels, as it is never a pleasant experience to find uninvited guests in one’s home, let alone in one’s toilet. And to confirm: yes, this is a hammerhead worm. Our reader may already be familiar with hammerhead worms, as she correctly identified this one, but in case she is not, the basic facts include: Hammerhead worms are predatory worms, though they are not significantly harmful to humans or pets (unless one keeps insects or snails for pests). They feed on insect larvae, snails, slugs, and other hammerhead worms. They are excellent trackers and possess amazing capabilities, such as the ability to regenerate severed body parts and to liquefy their prey.

Many a dangerous worm exists in this world, many of which are overestimated, but just as many of which are severely underestimated. This article will outline some of the worms that you may encounter that pose some level of threat toward yourself and others. For the sake of organizing the content of this article, we will split this up into three categories, namely parasites, venomous worms and marine worms (many of which you will never have to actually worry about).