Although the Gnezdo is slow in movement, its attack can be very damaging. It also can duplicate another human shaped swarm to confuse the player.
The Gnezdo "shoots" a slow moving swarm that has a distinctive shape. It is slow but when the player is caught in the swarm, it inflicts heavy damage and a QTE commences requiring the player to shake the analog stick to break free.
Once the Gnezdo releases its swarm, it is best to fall back. If the player is cornered, the player can avoid the swarm by sliding past it, provided the player doesn't accidentally slide into the swarm. Using Breakout and Defense Lv.3 can be effective when the player is caught in the swarm.
Gnezdo are extremely deadly, especially in tight areas, and should be killed as quickly and carefully as possible. Grenades and shotguns are your best bet at defeating the creature without taking damage. In particular, once the swarm has been dispersed, one acid round will instantly kill the queen. A grenade is recommended to first disperse the horde from a distance followed by moving in close to eliminate the queen as quickly as possible.
The queen does not stay still for very long, so shotguns are best suited due to their wide spread of shot. The Grenade Launcher can also be very helpful to defeat the Gnezdo. Ada's Crossbow also works well as it can kill the queen instantly in one shot, provided the player has good aim. If the queen is not killed after a few seconds, locate the horde and make sure they not moving in on you, as being caught by them will result in major damage. If it cannot be killed quickly, retreat and repeat the process until the enemy is defeated. Gnezdo can be very difficult to defeat and it advisable to avoid them if possible in order to conserve for ammo.