How do you think Sedna got its weird orbit?

Sedna is a trans-Neptunian object with a highly elliptical orbit having a perihelion of 76 Astronomical Units and an aphelion of 937 AUs. What do you think put Sedna into such a strange orbit, ranging from a close pass with the outer planets out into the clutter of the Oort Cloud. Astronomers think Sedna originally had a more regular orbit, but got pulled into the strange one it follows now. Do you think this disturbance happened recently? What most likely disturbed Sedna’s original orbit? What impact might its gravitational tug have on the orbits of the outer planets and dwarf planets, or on comet showers pulled from the Oort Cloud into the inner solar system?