One night my cat, Peanut, kept going by my front door, meowing like she wanted to go outside.
which was strange since she was an indoor gal. After about an hour, I opened the door to find another cat on my front step that had gotten hit by a car.
The thing was ABSOLUTELY MANGLED, literally half frozen to the point of having patches of frost on what was left of its fur, and its body had started to rot. It was so bad, It literally smelled dead.
Gently slid him into a box with a hockey stick and took him to the vet. It was in the teens that night, but had to keep the car windows down for the 25 minute drive because the smell was so overwhelming.
source : DAR Animal Rescue