Two-headed

is a physical mutation that grants the player an extra head.

The extra head granted by this mutation has an equip-able slot as a normal head does, as well as granting an additional face slot. However, AV and DV values granted by helmets and masks will be averaged across the two heads, meaning the player will have to wear two equipment pieces of the same type in order to gain the same AV and DV as normal. This does not affect Attribute bonuses granted by equipment, such as the Ego granted by wearing a.

Two Headed reduces the action cost of mental actions, such as using a mental mutation, by a mutation level based percentage. Additionally, it grants the player a mutation level based chance to "shake off" a mental status effect; see Effects Affected, below. These effects have a chance to either be removed immediately upon contracting them or every turn that the player has them for.

Creatures with two heads cannot be killed by decapitation so long as at least one of their heads remain. Rather than dying, creatures will bleed profusely when one of their heads is severed. If both heads are severed, the creature will instantly die.

Creatures that start with the mutation have a chance to have separate names for each head.

Formulas
The following formulas are used to determine mental action cost reduction and "shake off" chance based on mutation level.

Effects Affected
Two-headed affects all effects that are categorized as Mental, Negative, and Removable. It does not remove it if the effect is voluntarily applied to themself.

Advantages

 * Grants an extra head and face slot, allowing the player to wear additional equipment to gain extra Attribute bonuses, effects granted by modded items, or effects granted by artifacts
 * Synergizes well with mental mutations
 * Provides protection against many mental status effects
 * Prevents the player from dying instantly from decapitation

Disadvantages

 * Moderate cost on character generation
 * Halves AV and DV bonuses from equipment worn on the head and face, requiring the player to wear twice as many pieces for the same bonuses