There are several different types of jellyfish that people should be aware of. This is very important if you are going on vacation and you are worried about running into them. It is also interesting to know about them if you live in an area that is frequented by jellyfish. This article will explain a few different types of jellyfish if you are interested in learning about them.The cannonball jellyfish can also be called the cabbage head jellyfish. They are generally harmless and they will often wash up on beaches. It may reach sizes that are approximately 7 inches in diameter. It is not usually harmful if you simply brush up against in the water. It is actually edible and in Japan it is often enjoyed. They are usually dried before they are eaten and you do not want to eat the ones that have washed up on the beach.