The Chainsaw is an uncommon melee Weapon that can be found in various locations.
The Chainsaw has low base damage but attacks very rapidly, causing it to kill zombies very fast.
When the Chainsaw is selected as the active weapon it takes a second to 'wind up' as the character turns it on. Once it's activated it will begin to drain Gas as ammunition. The player can hold the primary attack button to do damage with it.
The Chainsaw can be still be used as a melee weapon should it run out of Gas. This is not recommended, however, as the Chainsaw has a 10% chance of breaking on hit when not using Gas.