Here's a pair of containers I made from the base of the bullwhip kelp. Its a very common seaweed along the California coast. I found these two washed up after high tide and cut the bulb-like base off. It was a very warm, sunny day and the sand was hot so I kept pouring it into the containers until they resembled damp leather. Before I went to sleep I filled them up with some very hot sand from near my campfire. After I woke up this is what they looked like. They kind of resemble gourds in color and consistency. The one on the left is 6" tall. They make an interesting pair of containers. I thought of using another bulb for a stopper. I'll try this when I go back to the ocean.
I've seen articles about similar projects at other sites. Also, if I remember correctly, there was an article about using the very long stem for rope. I'll have to try this, too.