The Headless Horseman

The Headless Horseman is a Harbinger that can appear in all environments of Chapters 1, 2, 3 and 4; replacing any other Horsemen. The head has 100 HP. The body's HP scales depending on what Chapter it is encountered- ranging from 60-300 HP.

Behavior
The Headless Horseman consists of two entities: The head and the body. Each performs attacks independently of the other.

The head has the following attacks:
 * Shoots 3 projectiles in a spread at Isaac.
 * Charges either left or right off-screen and continuing on from the opposite end of the screen. Continues until it has crossed the screen three times.
 * It performs this attack more often if Isaac is to its left or right.
 * This attack deals a full heart of damage.

The body has the following attack: Both the head and the body deal a whole heart of contact damage.
 * Periodically shoots red -like shots at Isaac leaving a large puddle of damaging Red Creep on impact.
 * This behavior is similar to Pestilence's second phase.

Trivia

 * The Headless Horseman appeared in the original The Binding of Isaac.
 * The Headless Horseman has been a common motif in Europe since the middle ages.
 * The boss art shows the head with both eyes even though its in-game sprite only has one.
 * The boss art shows the horse's head as brown even though its in-game sprite is black.
 * Delirium-form The Headless Horseman's horse resembles Famine's horse rather than The Headless Horseman's.

Seeds
0KCW ZG2A (first boss room) XEN1 CHXD (first boss room) 4Z9P HW9X (first boss room)

The Headless Horseman