In researching these little blue jellyfish, I have found that they are washing up in great numbers on shores around the world. From what I can find, the first picture shows a line of box jellyfish that litter the shore.
The next two shots are Portuguese man-o-war's. Scary looking things. In the first shot, that's a size 14 boot next to it for comparison.
Please feel free to correct me on the names.