An old physics teacher of mine had some good stories about hitting and killing things.
Once he hit a morning dove really hard. He said it was as if a balloon full of blood hit his windshield. In his rear view mirror he saw a cloud of feathers.
He also once hit a raccoon the size of a small child doing about 130km/h once. It was standing in the middle of the road so instead of gracefully rolling and getting mutilated under the car it (well, some of it) went through his grill and caused something like $2000 damage to his car. He said he could hear chunks of the animal bouncing around in the engine compartment for a few seconds afterwards.
A friend of my dad hit a huge crow once. WHAM! Right into the grill. After the thump he figured it was the end of it. About half an hour later the body started flapping against the hood of the van he was driving, causing bird bits to shoot up against the wind shield. When he pulled over he found that he couldn't pull the carcass out of the grill, it was stuck. So he had to saw the head off. :)
I was driving with a friend of mine once when a chipmunk ran out into our lane. He must have thought he didn't have enough time to get across so he turned around and ran in the other direction. Then he changed his mind again and ran back towards the median. He continued this running back and fourth until we hit him.
My grandparents were driving somewhere through the US, I can't remember where. They came over a ridge and hit a cow.
Long time ago there was a pond that would flood over this road by our house every spring. This pond had a HUGE frog population. People would slow down to drive over the flooded part of the road and cringe to the sound of "pop! pop! pop!"
A friend of mine was driving home to Norwood one night and a cop was, for some strange reason, riding his ass. All of a sudden his cherries came on and he shot past my friend at a good 150 km/h. Unfortunately there were three raccoons standing in the road right in the path of the cop. One of them got hit and flew off into the ditch, another got caught under the tire and left a long and gruesome trail up the road. The third one was lucky and got to just stand there and watch the carnage unfold.
I once saw an unreal shot of a deer that had been hit by a car on the news. Don't ask me how, but a car had managed to run over its head, causing its antler to impale the tire which caused the entire carcass to wrap itself around the wheel. Ouch.
This guy who lived in the hamlet where I used to live once got in his car and turned the key. He heard a horrible scream and some bad sounds. He opened the hood and found that a cat had been sleeping in the engine compartment. Its stomach was open and its intestines were wrapped around several of the belts. He got a knife and cut the belts, put the cat in a box and drove very quickly to the vet. The vet fixed the cat up as good as new and it became the man's pet. The vet couldn't do anything about his car though. Driving it without the belts had left it in worse shape than the cat was.