Thing type 106, Jetty-Syn Gunner, is a brown jetpack enemy used in Egg Rock Zone Act 2 that flies around and shoots bullets at the player. Compared to the Jetty-Syn Bomber, this Jetty-Syn is easier to kill, because it attacks head-on or from the side instead of swooping around above the player's head, but it also has a much longer projectile range and speed, making it more dangerous and more capable of surprise attacks. Its bullets also damage other enemies, including bosses.
The Jetty-Syn Gunner spawns 33 fracunits above the ground by default, which can be overridden by changing its Z position. Adding the Ambush flag will prevent it from moving and shooting. Placing large amounts of Jetty-syns in one room is considered bad design, especially over death pits. Since the player has to move at all times to avoid getting hit, this makes any platforming substantially harder, and will encourage the player to kill all enemies before moving on.