TAMING: Have your mount hit the archelon you want to tame (you might do this by accident will trying to save it), it'll aggro for a long time. Kite it onto the land and clear out any threats while you wait for it to catch up. Hop off your mount and whistle passive. The archelon will slowly chase down your tame allowing you to casually feed it bio-toxin or kibble from behind while picturing the steam roller scene from the first Austin Powers movie.