Swarm of Jellyfish on Bali, Indonesia ( Uluwatu Surf break )

Today, Friday May 30th around 1100 the surf break was inundated with a very dense swarm of jellyfish of varying sizes. The jellies ranged from 0.3 to 2 cm in size. The stings were initially quite mild but became more painful leading to most surfers leaving the water. I found a thin ~8 cm tentacle wrapped around my arm that cause much pain. Many surfers were complaining of the stings back on shore. Welting was apparent on affected exposed skin, my welts resolved without any kind of treatment (other than a cold water soapy shower. ) Most surfers said that they had never encountered this situation at Uluwatu before.