A Crawler has a 1% chance to spawn with a shooter rider. This means that a shooter spawner can extremely rarely spawn a Crawler Jockey.
Crawler Jockeys spawned in narrow enclosures can cause the shooter rider to die of suffocation, due to the Crawler scaling the walls.
The Shooter and the Crawler drop their drops when the respective one is killed.
The Shooter can drop 0 to 2 bones, and 0 to 2 bullets.
The Crawler can drop 0 to 2 string.
The Crawler controls the movement, so a Crawler Jockey will wander aimlessly in the day and only pursue the player at night or in dimly lit areas when the Crawler is hunting. The two creatures attack and take damage individually (i.e. if the Crawler is killed, the shooter will continue to attack and move, and vice-versa). If a Crawler Jockey jumps into water, the shooter will jump off the Crawler.
The shooter will turn and fire at the player as soon as it sees them no matter the time of day (although the shooter will quickly burn in sunlight, leaving the Crawler unharmed). A Crawler Jockey can attack two different players in Multiplayer Survival - this is caused by one player damaging one half of the Crawler Jockey and not the other. If the shooter shoots another monster, the creature will focus its attack on the shooter but not the Crawler being ridden, even after the shooter is killed. If the shooter on the Crawler Jockey is shot by another shooter, it will jump off and leave the Crawler to engage the shooter that shot it.
A Crawler Jockey can commit suicide - the shooter bullets can injure the Crawler and other times the Crawler's pouncing will run the shooter into its own bullet.