This is a small alcohol bottle, is very explosive, being filled with alcohol, and will detonate, spewing fire everywhere, when hit by a bullet. These are found in the ambulance on the wii version, with an unlimited supply available to use against the Batz. They are also found in the museum, in the large, demon root infested room in the upper right corner behind piles of wood and debris. They can be used against the Humanz which spawns into the room.
When you throw one, time in the game will slow so you can get a clearer shot. After finishing the ambulance level on the wii version, you will not be able to collect any alcohol bottles, or blood bags from the ambulance.