A toxic chemical called cantharidin is secreted from the legs and antennae of an Iron Cross Beetle when handled or touched, which causes painful blisters on human skin as well as on animals. If eaten in enough quantities, it can kill. While most people would refrain from eating beetles, this insect is sometimes unwittingly consumed by horses and livestock feeding on the plants where the beetle is present, causing death. Pets may also try to eat them. This same chemical has been used medicinally to kill and remove warts, so it helpful to people, too.
If seen, avoid contact with the Iron Cross Beetle and keep a wary eye for others that may be nearby.