Just found this in my donner kebab, can you identify what it is?
I strongly suspect that you are looking at a capsicum seed. In other words, you either had a piece of jalapeño, pickled pepperoni, or a sprinkle of pul biber (crushed red pepper). They are flat, about 2mm wide with that little tip.

The “worm” is actually the embryonic part of the seed. There are a few edible seeds which seem to have a “worm”, e.g. this Q/A on our site.