Is that a jelly? No it's some sort of suction cup piece of trash

We passed 5 different sized velella velella but we weren't certain it actually was a jelly until we saw the 2nd and 3rd ones. Initially we flipped it over since it was circle side up not the fin side. Upon flipping it over we saw the clear fun like arch which made me think that was the handle for a suction cup piece of trash. Although I was still hesitantt to pickk it up whether or not it was trash. We continued our stroll on the beach and found yet another two about 10 feet apart, both different sized. We inspected both of these two and noticed the little hair like tentacles on one of the two which definitely helped us see that this indeed was a sea creature, not trash. We continued back to camp to use the Internet to look up the description blue jellyfish with a clear fin.
Our shoreline is in Ventura, California. Temperature outside was about 80* and slightly breezy.