News reports are popping up in Texas of sightings of the hammerhead flatworm, an invasive, toxic worm species that likes heat and humidity and is reported to have arrived in Texas sometime in the ‘80s. Named for their flat, rounded heads, the worms can grow up to 15 inches long and are dangerous not only for the poisonous chemicals they secrete, but because they prey on beneficial earthworms that are crucial to the health of  gardens, forests, etc. 

If you see one, the Texas Invasive Species Institute (TISI) recommends the following:  

  • Don’t cut chop them up or cut off their heads—each segment will regrow, and you’ll have “created” even more worms 
  • Don’t touch them with bare hands—the poison they secrete can irritate skin. Use gloved hands, a paper towel or a stick to pick up the worm and place in a plastic bag with some salt or vinegar, tightly seal and throw in the trash 
  • Keep pets away from the worms as they can make animals sick if ingested 
  • If you accidentally touch one, wash your hands in warm, soapy water  

To help TISI better understand the range of this flatworm in Texas, send a photo of your find, along with location, to Ashley Morgan-Olivera at

More information: Hammerhead flatworm/ Hammerhead slug: Texas Invasive Species Institute (