Watcher Knight

Behavior
The Watcher Knights have three attacks:
 * Double Slash: Watcher Knight will swing their giant nail twice. Watcher Knight will swing horizontally first and follow it up with an overhead slash. Watcher Knight does move forward slightly with each swing.
 * Roll: Watcher Knight curls up into a spiky ball of death and rolls along the floor of the arena. Watcher Knight only stops rolling when it hits a wall so they'll cross the ENTIRE arena. Watcher Knight is completely invulnerable while rolling.
 * Bouncing Roll: Watcher Knight curls up into a spiky ball of death and bounces twice. When they do this attack, Watcher Knight will attempt to target The Knight, which can mean that Watcher Knight may simply bounce in place rather than travel around the arena. The first bounce takes Watcher Knight to the top of the arena and the second bounce takes them only to the middle. Once again, Watcher Knight is completely invulnerable when rolling.

Trivia
Рыцарь-бдитель
 * Given their name, they are presumably the deceased elite bodyguards of Lurien the Watcher.
 * Combined, the Watcher Knights have the highest total health of any other Boss in the game except for Dream Bosses, The Radiance, and Nightmare King Grimm.
 * Watcher knight is one of the few bosses who has to be defeated in order to beat the game.