I found this little jumpy cocoon thingie clinking approximately once every 4-5 seconds inside a metal lid. It's been jumping inside there for about a day since I first found it like that. It has a tiny flat mark on one of its sides which suggests that's how it initially stuck itself to something, and then got unstuck. What is this thing?
Here's a short web vid of it: https://giant.gfycat.com/IcyHarmfulCentipede.webm
And here's a static pic:
It stopped jumping around after about 1.5 days since I found it, and we decided to carefully cut it open with a paper knife. Inside was a white grub with a tiny orange dot on one of its ends, all foldy like a bendy part of a cocktail straw. It was still at first, but we sprayed it with water and put it on a leaf. It started moving around slowly, and looked like it was soaking up water. When we checked up on it later, it had disappeared and probably crawled away somewhere. Unfortunately, I didn't take any pictures of that, so it could have been anything.