The Seeker sentinel is a non-attackable NPC in the seeker sentinel puzzle in Daemonheim. It is found in the seeker spawn room, in which there is a large pit (in Furnished and Abandoned floors) or a pond (in the Frozen floors) in the middle of the room, forcing the player to go around the room by the sides, dealing with the Seeker spawns that block their path. If the player is seen by the seeker sentinel, they are teleported to a random side of the room and take low damage. The text in the chat box calls it "being seared". Because there is a chance that the player may be teleported to the side they need to go to, some players choose to be seen and seared until they reach the correct side.
There is an extremely large variant located in the middle of the Stalker dungeon, although it is non-interactive and only serves as scenery. The seeker sentinel in the Seeker dungeon rotates 45 degrees clockwise (as viewed from above) every five ticks.