The jerry can is a red gasoline container with a grey and yellow cap. It is located beside the wood chipper in the garden. The gasoline when poured inside a bucket is a lime yellow.
The jerry can's contents can be emptied into a bucket. That bucket can then be poured onto or splashed onto someone else. They will comment that it smells like gasoline and stand in place for ten seconds before running to the shower room. If a match is flicked onto a student covered in gasoline, they will catch on fire and burn to death.