Someone once donated roughly ten thousand feet of vinyl tubing of various diameters to Vector Space. Much to my frustration, it sat on the shelves unused for way too long, so I decided that I'd start coming up with project ideas that made use of it. When my youngest son randomly told me one day that he wanted a sprinkler with tentacle arms, I instantly had this brilliant idea.
After many iterations and complete failures, this was the design I ended on: two PVC pieces that make up the body, coupled together with a large bearing. The hose connects to the lower body piece with a threaded connector that I 3D printed. This part was pretty amazing to me, so I'll elaborate a little further. I needed to connect a hose to the PVC. Garden Hose threads are their own unique thing, so I found a female thread connector on Thingiverse, but the other end of it was just a barb without threads. So I modified the model in FreeCAD by putting male M16 threads (the largest tap I had at the time (how sad...)) on the opposite end of the connector. The thing printed perfectly and held water pressure with minimal leaking.
The upper body has four vinyl tubes connected at angles and a plug on the top of the PVC pipe to make sure whater goes out the vinyl tubes. When the water sprays out at an angle, it exerts a rotational force that causes the whole upper portion to spin around while children ride their bikes through, screaming with glee.
In the end it worked great and used about 2 feet of vinyl tubing.