Stolas
Stolas are stationary bird-like enemies found in Mausoleum. They will periodically fire a constellation projectile towards Isaac which follows him while periodically leaving behind a lingering stationary projectile every few moments. Whenever a projectile is created, the constellation projectile can also angle its trajectory loosely towards Isaac's position as it cannot travel in cardinal directions. All projectiles are linked to the first in a single chain by lasers, similar to 
Technology Zero. The initial constellation projectile will dissipate in a puff of light upon spawning the 8th projectile, and a Stolas will not fire another one until the previous has expired.
The constellation projectile will travel over obstacles and through walls, and cannot be destroyed by any means, including 
Lost Contact. It can only be stopped prematurely if it hits Isaac. Stolas can thus also target Isaac and fire the projectile towards him even when separated by obstacles.
The projectile chain will keep moving even after the Stolas has been killed.
Trivia
- Stolas draws inspiration from the demon prince of the same name in the Ars Goetia, often depicted as a crowned owl with long legs. He is said to teach astronomy, hence why Stolas fires star projectiles that move in a way that resembles a constellation.
Gallery
A Stola's appearance while firing projectiles.
Stola's constellation projectile.
Concept art for Stolas.
More (unhinged) concept art for Stolas.
