[doorgunner69]

Well, heck, no one swims in that ice cold water do they?

Other than being gross, they may or may not be stinging type jellyfish. But you go first to see.

[technically right]

Sahlla to Indiana Jones: Asps, very dangerous... you go first.

[Paul R.]

“Like many jellyfish Periphylla periphylla has large stinging cells on its tentacles that it uses to attack prey.”

http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/periphylla-periphylla/