In this animation you can see how odd Haumea's orbit is compared to Neptune's. The eight planets of the Solar System are pretty much in the same plane, called the ecliptic. (Imagine them all rolling around the Sun on a giant invisible table!) Here you can see that Haumea's orbit
is not only highly elliptical, but strongly tilted out of the ecliptic. The animation shows the dwarf planet's orbit from 2000 to 2300.
Credit: Phoenix7777 from data source HORIZONS System, JPL, NASA