What the heck did I see (insect)?

I’m sitting outside and I caught a glimpse of movement out of the corner of my eye. I looked up just in time to briefly see what I think was a very odd insect. I’d say it was about five inches long, and very skinny. It was greenish-yellow in color. I would have thought it was a piece of grass floating through the air, but I saw it move in some fairly complex ways, and it’s not all that windy outside right now. For a moment I thought it was a dragonfly, but its body was curving like a sine wave, and I’ve never seen a dragonfly do that, nor have I see a dragon fly so long and skinny, and I couldn’t see any wings. I didn’t see it for long and couldn’t locate it after its flight. What the heck?