Chainsaw (3.5e Equipment)
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The chainsaw is a complex tool crafted by gnomes which employs an engine of steam (amd sometimes magic) to drive a belt of blades around a vaguely sword-like projection. It is great for cutting through objects such as logs, and rare adamantine versions chew through solid iron walls. It is not intended for use as a weapon however. Those without proficiency take -6 to attack rolls, while those with proficiency still take -2. It may be used as a tool, proficient or not. All chainsaws are automatically masterwork.
The chainsaw does special things on a natural 1 and a natural 20. On a natural 1, the chainsaw has a 20% chance it may jam. In such a case, the device must be shut off and a Disable Device check of DC 20 is requires to bring the chainsaw back into working order. If the weapon is ever sundered, its fuel explodes, dealing 2d6 fire damage to its user.
On a natural 20 however, the chainsaw has bored into its target. In addition to the critical hit damage, the weapon has a 20% chance of lopping off a limb. Choose randomly from one of the limbs (typically 4 for two arms and two legs). The enemy loses that limb, and takes penalties appropriate. The head is not considered a limb for this purpose (and for balance, as it is not a Vorpal weapon).
Chainsaws gain +2 on Sunder checks and treat the hardness of the object as -2 less than normal (to a minumum of 0). Any enchantment bonus grants another -1 penalty per bonus.
Chainsaws which are not magical require fuel. It consumes 10g in alchemical fuel per encounter or for every minute used outside of battle. This fuel can be crafted with craft alchemy checks, generally distilled from organic sludge like oils.