What manner of sorcery is this?

I bought this flash drive in college a long time ago. My guess is around 8 years. Back then, unless you special ordered one, you could only get a 512MB or 1GB flash drive in most stores, and even then, they were on the more expensive side. I didn't need excessive space, just something so I could caddy files from home to school. This is a cheap-o 512MB one I bought at walmart. I haven't used it very much lately because I have a bunch of MicroSDs and I've been using those and the adapter, but the adapter just went out on me, so I've been using this again.

Yesterday, I noticed that there are a lot of files on it and that it should be pretty full by now. So I checked it. Then, checked it on a different computer. Then copied the files onto a hard drive to triple check and make sure that these numbers are real. And they are.

Now I remember in college having to dump this flash drive all the time because it filled up quickly. I don't know what's happening here. Someone explain it.

I've named the flash drive Merlin because of it's wizardry.