Honolulu Ocean Safety officials have issued a box jellyfish advisory at Ala Moana and Waikiki beaches on Oahu today.

The creatures usually arrive 8 to 10 days after a full moon. Lifeguards have posted warning signs at the beaches.

The invertebrates, named for the squarish shape of their bell-shaped body, can cause a painful sting on beachgoers, according to the Waikiki Aquarium.

Many lifeguards and doctors recommend rinsing the area with seawater and then applying a paste of unseasoned meat tenderizer and vinegar to the sting to help deactivate the toxin, the aquarium said.