Each Kingpin is made of segments, including a head and a tail. The amount of individual Kingpins that can appear, and the number of segments a Kingpin spawns with in the boss arena varies; however, Kingpin most commonly spawns in pairs with 12 segments each.
All Kingpins will spend most of the fight by weaving in and out of the ground while constantly chasing Isaac. They can burrow underneath rocks or leap on top and walk over them.
Occasionally, Kingpin's head will emerge from the ground and slither towards Isaac along the surface. During this, Kingpin will spit up to 5 projectiles at him, one at a time, before returning underground.
If there are multiple Kingpins, only one of them can perform this attack at a time.
When one of Kingpin's segments is destroyed, it releases 3 evenly-spaced projectiles with short range. These projectiles will linger in the air for several seconds before dropping.
Kingpin can divide and split into smaller copies of itself as its segments break, similarly to Larry Jr.
Kingpin moves faster the less segments it has.
Kingpin requires 2 segments to be alive — If a Kingpin worm would be at one segment left, it will die.
Notes
When encountered in their boss room, the total amount of segments shared between all Kingpins is typically 24 or 25 segments.
Any lingering blood projectiles Kingpin created after a segment died will all immediately fall to the ground once the room is cleared.
However, if Kingpin has been spawned after the room was previously clear, such as spawning from a wave in Boss Rush, the projectiles will fall immediately after they spawn.
Piercing tears will damage Kingpin's segments individually, making it especially effective against them.
This is despite the fact piercing tears are less effective towards other segmented bosses like Larry Jr. in Repentance, as they will no longer damage segmented enemies multiple times.
Although there is a "waiting" version of Kingpin that appears after the room would be cleared, it is very rare, only appearing in one room in the Chest and one room in the Ascent.
As Kingpin's name suggests, it is supposed to be a variation of Pin, though the two bosses share little in common other than the fact that they are both worms.
Kingpin's behavior of chasing Isaac by weaving in and out of the ground, and its ability to be cut in half, shares more in common with that of Larry Jr. and Weavers.
Gallery
A Kingpin's appearance when above ground and firing projectiles.
Drawing of Kingpin in the Bestiary and on Isaac's last will.
Caves.
Larry Jr.
Chest and one room in the 
Ascent.
Pin, though the two bosses share little in common other than the fact that they are both worms.
Bosses 