Autumn Elementals are non-attackable, non-interactive NPCs that are part of the Sorceress's Garden minigame. There are six of them in the garden that guard their precious Autumn Sq'irk tree. They guard the fruit of the Sq'irk tree that players attempt to steal. They teleport the player outside their to the central garden on sight.
As with all Sorceress's Garden elementals, they cannot use their teleother through walls, so if you time things just right, you can get one stuck behind a wall trying to get you, while other players can walk right on past it (However if the players stand too close to them or on a path they walk and still get too close to it will get you and teleport you out of the garden, players have been know to use this trick to teleport multiple players out of the garden). However, when you get a sq'irk, then go back in, it will still be targeting you.