All those things are deadly, or they can be. They are in the venomous species a box jellyfish. I can honestly say that I'm glad we don't have them over here, being as I love playing in the water. They are so tiny and one of the most venomous in the world. Thankfully for me, but not for Australia, they inhabit the waters in the northern part of Australia. Thanks for all your useful information. You never know what I'm going to need it.