That's what I'm thinking. It kinda looks like a drowned worm (you know, the ones you see on the driveways & sidewalks), a robin picked it up, flew towards it's nest, and accidentally dropped it right there. That's why it doesn't have the iridescent shiny color of a healthy worm AND why it looks slimy gooey. Next question is how did the rose get on the car? Did you cut the rose & laid it there as a tabletop? Or does your roses droop onto your car?