Funny smells and firewalls

My car started emitting a funny smell. It reminds me of the plastic-ey smell when using a hot glue gun. It started yesterday, specifically when I left work, because it didn’t smell when I drove to work, and the smell started within a minute of starting the car. I looked under the hood for melting hoses, loose wires, etc. but the only thing I noticed is that there is a hole in the firewall fabric. Not a melted hole, not cut, but a chunk torn out. It’s possible an animal got into my engine compartment, but anyways, could the smell be little pieces burning on the manifold?
The smell is not smokey, not acrid, and not metallic (like an electrical fire). I know it’s not brakes or belts, as there is no noise (and those smells are very distinct.) There’s no visible issues that I can find other than the firewall. Car runs normally, no overheating.