Guillotine

Guillotine is an unlockable passive item.

Effects[]

Isaac's head rotates around his body and can be used to inflict contact damage similar to a Cube of Meat. Blocking tears with Isaac's head does not damage Isaac. His tears still originate from his head, so the line of fire is no longer constant while standing still.
+1 damage.
-1 tear delay (increased rate of fire)
- Since this directly affects tear delay instead of changing the tears stat, it allows Isaac's rate of fire to go over the normal maximum rate.
- Tear delay decreases are more noticeable and are a greater increase to DPS when the tears stat is high.

+0.5 fire rate.
The head orbital deals 7 damage per tick or 105 damage per second ( 56 damage per second).

Isaac's body will spew a fountain of blood like a Gusher. This is purely cosmetic.
While Isaac's actual hitbox (his body) does not change, the position of the head can easily confuse the player on the body's exact position, making some tasks such as dodging tight bullet hell patterns or collecting pickups more difficult.
Items that apply contact damage and effects ( The Virus, Aries, etc.) do not apply to the head.

The head orbital ignores the normal three orbital cap used by items such as Cube of Meat and Sacrificial Dagger.
The orbital is larger than most other orbitals, making it easier to use both offensively and defensively.
- Despite changing size with Isaac, the orbital's hitbox does not change, which can be deceptive.
Using this item while near a wall may cause the head to go inside the wall while rotating and block tears shot.

BFFS!: Though the head doesn't physically increase in size, it now deals 2x contact damage.
Box of Friends: Adds another rotating head on each use. Each head increases damage and tears and blocks projectiles. With more heads, it is easier to locate the position of the body, and Box of Friends can be used multiple times in the same room to continue gaining heads.
Spectral tears: Guillotine can move Isaac's head into walls and obstacles, which results in lots of wasted shots. Spectral tears allow all shots to have a chance to hit instead of being wasted.
The Twins: Has a chance to add another head, increasing damage and tears.

Berserk! / The Forgotten / Tainted Samson / Tainted Forgotten: The melee weapon is swung from the body instead of the head.
Big Fan: Slows down the head orbital.
Diplopia: Adds another head and further increases tears and damage, but only fires tears from one head.
Duct Tape: Causes tears to be fired from far below and to the right of Isaac. This causes tears to be out of bounds unless Isaac is standing in the top-left corner of the room.
- Tears are fired from whatever position the head is stuck in.
Guardian Angel: Does not increase the head's rotation speed.
Mom's Knife: The knife fires from Isaac's body, not his head.
Sacrificial Altar: The head orbital cannot be sacrificed.
Scissors: Isaac will have two heads: the one from Scissors, which will shoot as normal, and the Guillotine one, which only acts as an orbital.
Spin to Win: Affects the head, which boosts its damage and defense properties at the cost of shots being harder to hit.
Spirit Sword: The sword is swung from Isaac's body, not his head. This also applies to the sword's projectiles.
Tainted Lilith: The baby fires from Lilith's body, not her head.
Tiny Planet: Tears may fire from the head, but they orbit the body.
Tractor Beam: Despite the beam moving with Isaac's head as it orbits the body, tears will be fired from the body.
Transcendence: Makes Isaac's body invisible, leaving only a shadow where his body is. As a result, Isaac becomes very difficult to control.

A guillotine is an execution device that kills by severing its victim's head. It gained notoriety during the French Revolution where it was used to kill 17,000 people during the period known as the "Reign of Terror."
If Isaac has items that visually change his hands, the effect applies to Isaac's head too. For example, when having Bursting Sack, Isaac's body and head will both hold a sack while there are two extra hands added to the head.
With Number One, Isaac will still shoot from his head. The implications of this baffle all lore enthusiasts.