Stone brewing smoked porter. I couldn't take more than than a few sips before I poured out the rest. It tasted like pure liquid smoke.
The other one that was awful was Mission Brewery hefeweizen. It was anything but a hef. It was clear, felt like I was drinking a bad ale. Dull flavors, a strange aftertaste. I managed to finish the 6 pack but I didn't really enjoy it.