Ants sometimes act like a liquid, other times a solid

Fire ants aren’t that odd but their behavior certainly is.  Fire ants are a scourge of the southern United States.    Wikipedia says: “in the US the FDA estimates that more than $5 billion is spent annually on medical treatment, damage, and control in Red Imported Fire Ant infested areas. Furthermore, the ants cause approximately $750 million in damage annually to agricultural assets, including veterinarian bills and livestock loss, as well as crop loss.”  They are an invader species and truly a pest.