What's going on?

What's going on?

Observation - What's going on? - UK and Ireland. Description: I thought I'd discovered a new kind of fly. It turned out it was dead in the end (and I don't know what fly it is either). But in particular, what is that stripy stuff encasing this fly's body?

I thought I'd discovered a new kind of fly. It turned out it was dead in the end (and I don't know what fly it is either). But in particular, what is that stripy stuff encasing this fly's body?