I must have seen an article on them a few weeks ago. They sound icky, and I will squish them if I see them.
Years ago Discover Magazine ran an article in the April issue about a worm that lived in the arctic, one whose body heat rose and enabled them to bore through the arctic ice. It was very interesting, and convincing. Turns out, it was an Aprils Fool hoax, and every one had a good laugh. Except me. I still resent them for using their extreme credibility to play a senseless joke on their adoring readers.
However, gullible me believes the hammer head worm is a real thing, and will be on the look out.
At one time, researchers were concerned terrestrial planarians might damage plants. Over time, they were deemed harmless to greenery, but then a more insidious threat appeared. Hammerhead worms have the potential to exterminate earthworm populations. Earthworms are vital because they aerate and fertilize the soil. Hammerhead worms are considered a threatening invasive species. Some methods used to control slugs also work on flatworms, however, their longterm impact on ecosystems has yet to be fully determined.